Bits

A personal dictionary of concepts, mental models, and ideas I find useful.

Philosophy

Amor Fati

Latin for "love of fate." Not just accepting what happens, but embracing it. Treat each moment as something to be welcomed. Turns obstacles into fuel.

"Do not seek for things to happen the way you want them to; rather, wish that what happens happen the way it happens: then you will be happy."

— Epictetus

Antifragile

Things that gain from disorder, volatility, and stressors. Beyond resilience or robustness. Actually becoming stronger when exposed to chaos. Builds optionality and survives the Lindy test.

"Some things benefit from shocks; they thrive and grow when exposed to volatility, randomness, disorder, and stressors."

— Nassim Nicholas Taleb

Dichotomy of Control

The foundational Stoic principle. Some things are within your control, others are not. Focus only on your own actions, judgments, and responses. Let go of everything else.

"Make the best use of what is in your power, and take the rest as it happens."

— Epictetus

Fortitude

Courage in facing pain, danger, or adversity. Mental and emotional strength. Not the absence of fear but action despite it. One of the four cardinal virtues alongside prudence, justice, and temperance.

Freedom

The ability to choose how you spend your time, energy, and attention. Not the absence of constraints, but the presence of options. Often requires discipline to create and maintain.

Lindy Effect

The longer something non-perishable has survived, the longer its remaining life expectancy. A book that has been in print for 100 years will likely be in print for another 100.

— Nassim Nicholas Taleb

Memento Mori

Latin for "remember you will die." Not morbid, but clarifying. Death awareness as a tool for living fully. When you remember time is finite, trivial concerns fade. What matters becomes obvious.

"You could leave life right now. Let that determine what you do and say and think."

— Marcus Aurelius

Premeditatio Malorum

The premeditation of evils. Deliberately visualizing worst-case scenarios to reduce their power over you. Not pessimism, but preparation. When you have imagined the worst, you are ready for anything.

"What is quite unlooked for is more crushing in its effect, and unexpectedness adds to the weight of a disaster."

— Seneca

The Hard Path

What stands in the way becomes the way. Every obstacle contains opportunity. The impediment to action advances action. Adversity is not something to endure, but something to use.

"The impediment to action advances action. What stands in the way becomes the way."

— Marcus Aurelius

Psychology

Adaptability

The capacity to adjust to new conditions. Not just surviving change but thriving through it. Flexibility without losing core identity. In a world that changes fast, adaptability beats raw strength.

Dopamine

The reward chemical. Released in anticipation of reward, not when receiving it. Drives motivation and goal-seeking. Easy hits (social media, junk food) hijack the system.

Ego

Unhealthy belief in your own importance. Makes you defensive, closed to feedback, focused on appearing smart rather than being effective. Stay a student.

"If you want to do something big in your life, you cannot have an ego. Ego is the enemy of what you want and of what you have."

— Ryan Holiday (paraphrased)

Endorphins

The painkiller. Released in response to stress or discomfort to mask pain and create euphoria. Triggered by exercise, laughter, and pushing through physical challenges. The source of "runner's high" and why hard workouts feel good after.

Fear Setting

Defining your fears in detail instead of your goals. List the worst that could happen, prevention steps, and repair actions. Often reveals the downside is smaller than imagined. The opposite of goal setting.

"We suffer more often in imagination than in reality."

— Seneca (via Tim Ferriss)

High Agency

Believing you can affect change, then acting on it. High agency people find a way or make one. They skip waiting for permission. When told something is impossible, they ask "how might we?"

Motivation

The desire to act. Unreliable as a primary driver. Comes and goes with mood and energy. Better to build discipline than wait for motivation.

"People often say that motivation does not last. Well, neither does bathing - that is why we recommend it daily."

— Zig Ziglar

Oxytocin

The bonding chemical. Released through physical touch, trust, and social connection. Strengthens relationships and builds loyalty. Hugs, eye contact, and acts of generosity all trigger its release.

Passion

Deep enthusiasm and drive for something. Often misunderstood as something you find rather than something you develop. Passion follows mastery - the better you get at something, the more you tend to love it.

"Passion is not something you follow. Passion is something that will follow you as you put in the hard work to become valuable to the world."

— Cal Newport (paraphrased)

Resilience

The ability to recover from setbacks and return to baseline. Bouncing back, not breaking. Important, but limited. The next level is antifragile: getting stronger from stress, not just surviving it.

Serotonin

The mood stabilizer. Released when you feel significant or important. Recognition, respect, status. Sunlight, exercise, and reflecting on past achievements boost it. Low serotonin links to depression and anxiety.

Tolerance

The ability to endure difficulty or discomfort. Building capacity for what is hard. Different from acceptance. Tolerance is bearing the weight. Acceptance is putting it down.

Productivity

Consistency

Showing up every day regardless of motivation. Small actions repeated beat occasional heroic efforts. Not talent, not luck. Just relentless repetition.

"We are what we repeatedly do. Excellence, then, is not an act, but a habit."

— Will Durant (summarizing Aristotle)

Deep Work

Distraction-free concentration that pushes your cognitive limits. Rare. Valuable. Increasingly difficult in an age of constant connectivity. The superpower of the knowledge economy.

"Deep work is the ability to focus without distraction on a cognitively demanding task."

— Cal Newport

Discipline (Hormozi)

The strongest form of self-love. Ignoring current pleasures for bigger rewards. Caring enough about your future self to make hard choices today.

"Discipline is the strongest form of self-love. It's ignoring current pleasures for bigger rewards to come."

— Alex Hormozi (attributed)

Discipline (Jocko)

Doing what needs to be done, regardless of how you feel. The bridge between goals and accomplishment. Compounds over time. Creates freedom through structure.

"Discipline equals freedom."

— Jocko Willink

Discipline (Williamson)

Maturity is choosing discipline over motivation. Motivation is fleeting. Discipline shows up every day regardless of how you feel.

"The emotionally immature man seeks motivation to do something hard one time, the emotionally mature man uses discipline to do something hard a thousand times."

— Chris Williamson

Eat the Frog

Do your hardest task first thing in the morning. If you have to eat a live frog, get it over with early. Nothing worse will happen the rest of the day. Willpower is finite. Use it on what matters most.

"Swallow a toad in the morning and you will encounter nothing more disgusting the rest of the day."

— Nicolas Chamfort (popularized by Brian Tracy)

Effectiveness

Doing the right things. Choosing activities that actually move you toward your goals. More important than efficiency. Being effective at the wrong thing is still failure, just faster.

"Efficiency is doing things right; effectiveness is doing the right things."

— Peter Drucker

Efficiency

Doing things right. Minimizing waste, time, and effort. Maximum output from your inputs. Important, but useless without effectiveness.

"There is nothing so useless as doing efficiently that which should not be done at all."

— Peter Drucker

Habit

Behavior repeated enough to become automatic. The compound interest of self-improvement. Small changes appear to make no difference until you cross a critical threshold.

"You do not rise to the level of your goals. You fall to the level of your systems."

— James Clear

Parkinson's Law

Work expands to fill the time available for its completion. Give yourself a week, it takes a week. Give yourself a day, it takes a day. The antidote is artificial deadlines and time constraints.

"Work expands so as to fill the time available for its completion."

— Cyril Northcote Parkinson

Priority

The thing that matters most right now. Originally singular - you can only have one priority. When everything is a priority, nothing is. Clarity on priority is clarity on what to say no to.

"The word priority came into the English language in the 1400s. It was singular. It meant the very first or prior thing. It stayed singular for the next five hundred years."

— Greg McKeown

Productivity

Getting meaningful things done. Not about being busy or checking off tasks, but about making progress on what actually matters. The compound effect of consistent, focused output over time.

"Productivity is never an accident. It is always the result of a commitment to excellence, intelligent planning, and focused effort."

— Paul J. Meyer

Scaling Yourself

The transition from individual contributor to force multiplier. Your impact is no longer measured by your own output but by how much you enable others. Teaching, delegating, and building systems that work without you.

Time Blocking

Scheduling specific blocks of time for specific tasks. Protecting your calendar from reactive chaos. What gets scheduled gets done. Turns intentions into commitments.

Leadership

Context Not Control

Give people the information they need to make good decisions rather than telling them what to do. Control does not scale; context does. When people understand the why, they can figure out the how themselves.

"The best managers figure out how to get great outcomes by setting the appropriate context, rather than by trying to control their people."

— Reed Hastings

Disagree and Commit

Voice your disagreement during the debate, but once a decision is made, commit fully to executing it. Prevents endless deliberation and passive resistance. You can disagree without being disagreeable, then align without resentment.

"Have backbone; disagree and commit. Leaders are obligated to respectfully challenge decisions when they disagree. Once a decision is determined, they commit wholly."

— Amazon Leadership Principle

Extreme Ownership

Taking complete responsibility for everything in your world. No excuses, no blame, no finger-pointing. When something goes wrong, look in the mirror first. Leaders who own their failures earn the right to share in success.

"The leader is truly and ultimately responsible for everything. That is Extreme Ownership."

— Jocko Willink

First Team

Your peer group of fellow leaders is your first team, not the team you lead. When leaders optimize for their own teams at the expense of peers, the organization suffers. Cross-functional alignment requires putting the leadership team first.

— Patrick Lencioni

Modeling Behavior

Children learn more from what you do than what you say. They are always watching. How you handle stress, treat others, show up. Be the person you want them to become.

On-call

Being available to respond to incidents outside business hours. The price of running production systems. Should be compensated, sustainable, and shared. You build it, you run it.

One-on-Ones

Regular private meetings between manager and direct report. The most important meeting on your calendar. Not for status updates. For coaching, feedback, career growth, building trust. Their meeting, not yours.

"The one-on-one is your direct report's meeting, not yours."

— Andy Grove (paraphrased)

Psychological Safety

The belief that you can take risks without being punished or humiliated. Teams with high psychological safety learn faster, innovate more, and perform better. People need permission to fail, ask questions, and challenge ideas.

"Psychological safety is not about being nice. It is about giving candid feedback, openly admitting mistakes, and learning from each other."

— Amy Edmondson

Radical Candor

Caring personally while challenging directly. The sweet spot between being a jerk (challenging without caring) and being ruinously empathetic (caring without challenging). Kind honesty beats dishonest kindness.

"Radical Candor is not brutal honesty. It is humble, helpful, immediate, in person, and not about personality."

— Kim Scott

Servant Leadership

Leaders exist to serve their teams, not the other way around. Remove obstacles. Provide resources. Shield from distractions. The measure of leadership is not what you accomplish but what you enable others to accomplish.

"The servant-leader is servant first. It begins with the natural feeling that one wants to serve."

— Robert K. Greenleaf

Strategy

Compounding

Growth that builds on itself. Small consistent gains become extraordinary results. Applies to money, knowledge, relationships, skills. Patience is key. Most gains come at the end.

"Compound interest is the eighth wonder of the world. He who understands it, earns it; he who does not, pays it."

— Albert Einstein (attributed)

Flywheel

A self-reinforcing loop where momentum builds on itself. Each push makes the next push easier. Hard to start but unstoppable once spinning. Amazon's flywheel: lower prices attract customers, which attracts sellers, which lowers prices.

— Jim Collins

Leverage

Force multipliers that let you accomplish more with less. Traditional leverage: labor and capital. New leverage: code and media. They work while you sleep, cost nothing to replicate, and scale infinitely.

"Give me a lever long enough and a fulcrum on which to place it, and I shall move the world."

— Archimedes

Mission

The purpose of an organization. Why it exists and what it does. Present tense, action oriented. Vision is where you are going. Mission is how you get there and why it matters. Guides daily decisions and priorities.

Moat

A sustainable competitive advantage that protects a business from competitors. Like a castle moat, it creates distance between you and threats. Can be built through network effects, brand, cost advantages, switching costs, or unique assets.

"In business, I look for economic castles protected by unbreachable moats."

— Warren Buffett

Network Effects

When a product becomes more valuable as more people use it. The phone is useless alone but invaluable when everyone has one. Creates winner-take-all dynamics and powerful moats. The strongest form of competitive advantage in the digital age.

OKR

Objectives and Key Results. A goal-setting framework where objectives define what you want to achieve and key results measure how you know you achieved it. Objectives are qualitative and inspiring. Key results are quantitative and specific.

"What gets measured gets managed."

— Often attributed to Peter Drucker (paraphrased)

Optionality

Having choices and flexibility. The value of being able to choose between alternatives, especially under uncertainty. More options = more upside with limited downside.

POMA

Pulled Out of My Ass. A made-up number with no real basis. Unlike a SWAG, no reasoning behind it. Pure improvisation when someone demands a number.

Product-Market Fit

When a product satisfies strong market demand. You stop pushing the product and customers start pulling it from you. Everything before PMF is searching; everything after is scaling. You know you have it when growth feels inevitable.

"Product-market fit means being in a good market with a product that can satisfy that market."

— Marc Andreessen

Reversible Decisions

Two-way doors you can walk back through. One-way doors you cannot. Most decisions are reversible. Make them quickly. Save the careful deliberation for irreversible ones.

"Some decisions are consequential and irreversible or nearly irreversible – one-way doors – and these decisions must be made methodically, carefully, slowly. But most decisions are changeable, reversible – two-way doors."

— Jeff Bezos

Runway

The amount of time a company can operate before running out of money. Calculated as cash divided by monthly burn rate. Runway determines urgency, risk tolerance, and strategic options. More runway means more shots on goal.

S.M.A.R.T. Goals

Goals that are Specific, Measurable, Achievable, Relevant, and Time-bound. A framework for setting clear objectives. Vague goals fail. S.M.A.R.T. goals force clarity about what success looks like and when it should happen.

Second-Order Thinking

Thinking beyond immediate consequences to what happens next. First-order thinking asks "What happens if I do this?" Second-order asks "And then what?" Most people stop at first-order, which is why second-order thinkers have an edge.

"Failing to consider second- and third-order consequences is the cause of a lot of painfully bad decisions."

— Ray Dalio

Skin in the Game

Having personal risk in the outcome of your decisions. Symmetry between risk and reward creates accountability. Never trust advice from those who do not bear the consequences. The captain should go down with the ship.

"Do not pay attention to what people say, only to what they do, and how much of their necks they are putting on the line."

— Nassim Nicholas Taleb

SLA

Service Level Agreement. A contract defining expected service quality between provider and customer. Includes consequences for missing targets. The business wrapper around SLOs.

SLO

Service Level Objective. Internal target for service reliability. "99.9% of requests succeed within 200ms." More ambitious than SLAs to create a buffer. Measured by SLIs.

Strategy

The overall plan to achieve long-term goals. Answers "what" and "why." Choosing where to play and how to win. Tactics answer "how."

SWAG

Sophisticated Wild Ass Guess. An informed estimate based on experience and intuition rather than precise data. Better than a POMA.

Tactics

The specific actions to execute a strategy. Answers "how." The concrete steps taken day-to-day. Good tactics without strategy is noise before defeat.

Vision

The picture of a future state the organization aims to create. Where you want to be. Aspirational and long-term. Inspires and aligns people toward a common destination. A good vision is clear enough to guide decisions but bold enough to motivate.

Engineering

Architect's Dilemma

The tension between deciding now with incomplete information versus waiting for clarity that may never come. Architecture decisions made too early are wrong; made too late are costly. The skill is knowing when you have just enough information.

Back Pressure

When a system is overwhelmed, push back on the caller instead of falling over. Queues, rate limits, 429s. A system that says "slow down" is better than one that silently drops requests.

Bikeshedding

Spending disproportionate time on trivial issues while ignoring important ones. A committee will debate bike shed paint colors longer than nuclear reactor plans. Everyone has an opinion on paint.

Blue-Green Deployment

Run two identical environments. Deploy to the idle one. Switch traffic over. Instant rollback by switching back. Zero downtime. The cost is running double infrastructure.

Boring Technology

Choosing proven, well-understood tools over shiny new ones. Every technology choice has a complexity budget. Spend it on your core problems, not infrastructure surprises. Boring is a feature.

"Let us be boring in the things that do not matter so we can be interesting in the things that do."

— Dan McKinley (paraphrased)

Build vs Buy

Build when it gives you competitive advantage. Buy when it is commodity. The hidden cost of building: maintenance forever.

Canary Release

Roll out changes to a small subset of users first. Watch the signals. If something breaks, only a fraction of users are affected. Expand gradually or roll back fast.

CAP Theorem

Distributed systems can only guarantee two of three: Consistency, Availability, Partition tolerance. You must pick. Most real systems choose AP or CP. Understanding the tradeoff matters more than memorizing the acronym.

Change Management

Controlled process for making changes to production. Review, approval, rollback plan. Reduces risk by forcing you to think before you act. Too little causes outages. Too much causes slowness.

Circuit Breaker

Stop calling a failing service. Let it recover. Try again later. Prevents one failure from cascading through the entire system. Three states: closed (normal), open (failing), half-open (testing recovery).

Conway's Law

Organizations design systems that mirror their own communication structure. If you have four teams building a compiler, you will get a four-pass compiler. Want a different architecture? Change the org chart first.

"Any organization that designs a system will produce a design whose structure is a copy of the organization's communication structure."

— Melvin Conway

Dead Letter Queue

Where failed messages go to wait. Instead of losing them or retrying forever, park them for inspection and replay. A safety net for async systems. Unprocessed is better than lost.

DORA Metrics

Four metrics that predict software delivery performance. Deployment frequency, lead time, change failure rate, and MTTR. Elite teams deploy on demand with sub-hour lead times.

— Accelerate (Forsgren, Humble, Kim)

DRY vs WET

Don't Repeat Yourself vs Write Everything Twice. DRY is a good default, but premature abstraction is worse than a little duplication. Duplicate first. Abstract when the pattern is clear.

E.164

The international standard for phone number formatting. Up to 15 digits. Always starts with a country code. +14155552671, not (415) 555-2671. Store numbers in E.164. Format them for display.

Eventual Consistency

Data will be consistent, just not right now. The tradeoff you make for availability and speed. DNS, caches, replicated databases. Most systems tolerate it. Users barely notice.

Feature Flags

Ship code without shipping features. Toggle functionality on or off without deploying. Decouple deploy from release. Test in production. Roll out gradually. Kill switch included.

Four Golden Signals

Google SRE framework for monitoring distributed systems. If you can only measure four things, measure these: latency, traffic, errors, and saturation.

— Google SRE Book

Idempotency

Running an operation multiple times produces the same result as running it once. Critical for retries, webhooks, and APIs. If a payment request times out, you need to safely retry without double charging.

Incident vs Problem

An incident is the fire. A problem is what started it. Fix incidents fast to restore service. Solve problems to prevent recurrence. Conflating them leads to slow incident response or repeated outages.

ISO 8601

The international standard for date and time. 2024-01-15T14:30:00Z. Year first, then month, then day. Sorts correctly as text. No ambiguity between US and European formats. Use it everywhere.

Observability

Logs, metrics, traces. The three pillars. Not just monitoring what you expect to fail, but being able to ask new questions when something unexpected happens. You cannot fix what you cannot see.

Postmortem

Blameless analysis after incidents. What happened, why, and how to prevent it. Focus on systems, not people. Learning over finger-pointing. The goal is fewer future incidents, not assigning fault.

RFC 1918

The RFC that defines private IP address ranges. 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Not routable on the public internet. Every home router, every corporate network, every VPC.

Rubber Duck Debugging

Explaining your code line-by-line to an inanimate object (traditionally a rubber duck) to find bugs. The act of articulating the problem forces you to think through it systematically. Often you find the bug before finishing the explanation.

Runbook

Step-by-step procedures for operational tasks. What to do when the alert fires. Reduces reliance on tribal knowledge and makes response repeatable. If you do it twice, write a runbook.

Strangler Pattern

Gradually replacing a legacy system by building new functionality around it, slowly strangling the old system until it can be removed. Named after strangler figs that grow around trees. Safer than big-bang rewrites.

— Martin Fowler

Tech Radar

A framework for tracking technology readiness and adoption. Categories like Adopt, Trial, Assess, and Hold help teams make consistent choices. What worked yesterday may not work tomorrow. Stay curious but skeptical.

Technical Debt

Future rework cost from choosing the fast solution now. Like financial debt, it can be leverage or burden. Strategic debt lets you ship and learn. No point going bankrupt chasing 100% test coverage. Just know your balance.

"Shipping first time code is like going into debt. A little debt speeds development so long as it is paid back promptly with refactoring."

— Ward Cunningham

Trunk-Based Development

Everyone commits to main. Short-lived branches. Small, frequent merges. Opposite of long-lived feature branches. Reduces merge conflicts. Pairs well with feature flags and strong CI.

Twelve-Factor App

Twelve principles for building modern, deployable, scalable software. Config in environment variables. Stateless processes. Disposable instances. Logs as event streams. Written by Heroku. Still holds up.

YAGNI

You Aren't Gonna Need It. Don't build for hypothetical future requirements. Solve today's problem today. Speculative features add complexity, cost maintenance, and usually miss the mark anyway.

Yak Shaving

The endless series of small tasks you have to do before you can do the thing you actually want to do. You wanted to deploy a feature but first you need to update the CI pipeline, but first you need to fix the tests, but first... Named after a Malcolm in the Middle episode.

Metrics

ARPU

Average Revenue Per User. Total revenue divided by number of users. Shows how much value each customer brings. Rising ARPU means better monetization or moving upmarket. Falling ARPU might signal pricing issues or market shift.

Burn Rate

Monthly cash spend exceeding income. How fast a company consumes its reserves. Divide cash on hand by burn rate to get runway. Gross burn is total spend. Net burn accounts for revenue.

CAC

Customer Acquisition Cost. Total sales and marketing spend divided by new customers gained. The price of growth. Compare against LTV to know if growth is sustainable.

CAPEX

Capital Expenditures. Money spent on long-term assets. Equipment, property, major infrastructure. Depreciated over time rather than expensed immediately. Heavy CAPEX businesses need more capital to grow.

Cash Flow

Actual money moving in and out. Different from profit because of timing, depreciation, and non-cash items. A profitable company can die from negative cash flow. Cash is oxygen.

Change Failure Rate

Percentage of deployments causing failures in production. One of the DORA metrics. Elite teams stay under 15%. Speed and stability are not tradeoffs.

Churn

The rate at which customers leave. Usually measured monthly or annually. The silent killer of growth. High churn means pouring water into a leaky bucket. Fix retention before scaling acquisition.

COGS

Cost of Goods Sold. The direct costs to produce what you sell. For software, often hosting, infrastructure, and support. Subtract from revenue to get gross margin. Lower is better.

Conversion Rate

Percentage completing a desired action. Visitors to signups. Signups to paying customers. Free to paid. Small improvements compound across the funnel. A 2% conversion doubled is worth more than traffic doubled.

Deployment Frequency

How often you deploy to production. One of the DORA metrics. Elite teams deploy on demand, multiple times per day. Low performers deploy monthly or less.

EBITDA

Earnings Before Interest, Taxes, Depreciation, and Amortization. A proxy for operating cash flow that strips out financing and accounting decisions. Popular but controversial. Critics argue it ignores real costs that businesses must eventually pay.

"Every time you see the word EBITDA, you should substitute the words bullshit earnings."

— Charlie Munger (attributed)

Errors

Rate of failed requests. One of the four golden signals. Includes explicit failures (500s), implicit failures (200 with wrong content), and policy violations (slow responses).

Gross Margin

Revenue minus cost of goods sold, as a percentage. What remains after direct costs. Software has high margins (70-90%). Retail has low margins (20-50%). Determines how much is left to cover operating expenses.

Growth Rate

Percentage change over time. MoM (month-over-month) for early startups. YoY (year-over-year) for mature businesses. YoY smooths seasonality. Consistent growth beats sporadic spikes.

Latency

Time to service a request. One of the four golden signals. Distinguish between successful and failed requests. A fast error is still a bad experience.

Lead Time for Changes

Time from code commit to running in production. One of the DORA metrics. Elite teams measure in hours. Shorter lead times mean faster feedback and lower risk.

LTV

Lifetime Value. Total revenue expected from a customer over the entire relationship. Also called CLV (Customer Lifetime Value). The foundation of unit economics. If CAC exceeds LTV, every new customer loses money.

LTV:CAC Ratio

The ratio of customer lifetime value to acquisition cost. The health check for growth. 3:1 is the benchmark. Below that, acquisition is too expensive. Much higher, and you might be underinvesting in growth.

Market Cap

Market capitalization. Share price multiplied by total shares outstanding. The market value of a public company. Not what it cost to build. Not what assets are worth. What buyers will pay today.

MAU

Monthly Active Users. The count of unique users who engage with a product in a given month. A pulse check on product health and reach. Growing MAU means people keep coming back. Flat or declining MAU signals trouble.

MRR & ARR

Monthly Recurring Revenue and Annual Recurring Revenue. The predictable income a subscription business can count on. MRR times twelve equals ARR. The heartbeat of SaaS. Growth, churn, and expansion all show up here first.

MTTR

Mean Time to Recovery. How fast you restore service after a failure. One of the DORA metrics. Elite teams recover in under an hour. Prioritize recovery speed over preventing all failures.

Net Income

The bottom line. Revenue minus all expenses, taxes, and interest. What the business actually earned. Profitable on paper does not mean cash in the bank. Compare with cash flow for the full picture.

NRR

Net Revenue Retention. Revenue kept from existing customers, including expansions and contractions, excluding new sales. Over 100% means customers spend more over time. The best SaaS companies exceed 120%.

Operating Margin

Operating income divided by revenue. Profit from core business operations before interest and taxes. Shows how efficiently the business runs day to day. Ignores financing decisions and tax strategies.

OPEX

Operating Expenses. Day-to-day costs to run the business. Salaries, rent, marketing, software subscriptions. Recurring and ongoing. Easier to cut than CAPEX but often where the value is created.

P/E Ratio

Price to Earnings. Stock price divided by earnings per share. What investors pay for each dollar of profit. High P/E signals growth expectations. Low P/E signals value or doubt. Meaningless for unprofitable companies.

Revenue

The total income generated from selling goods or services. The top line. Not profit. Revenue feeds the business, but what matters is what remains after costs. Revenue is vanity, profit is sanity, cash is reality.

ROI

Return on Investment. The gain or loss relative to the cost. Calculated as (return minus cost) divided by cost. The universal measure of whether something was worth it. High ROI means efficient use of resources.

Saturation

How full your service is. One of the four golden signals. CPU, memory, disk, network capacity. Most systems degrade before hitting 100%. Know your limits.

SLI

Service Level Indicator. The actual measurement of service behavior. Request latency, error rate, throughput. The data that tells you if you are meeting your SLOs.

Traffic

Demand on your system. One of the four golden signals. Requests per second for web services. Transactions or sessions for databases. Shows how busy you are.

Culture

Carte Blanche

French for "blank card." Complete freedom to act as you wish. Full authority to make decisions without approval. A gift of trust and a test of judgment.

Dolce Far Niente

Italian for "the sweetness of doing nothing." Guilt-free relaxation without purpose or productivity. Rest is not laziness. It is essential.

Fika

Swedish ritual of coffee and connection. More than a coffee break. An intentional pause to slow down, enjoy the moment, and connect with others. Wellbeing over productivity.

Hygge

Danish concept of cozy contentment. Creating warmth and enjoying simple pleasures: candlelight, good company, comfort food, warm blankets. Not about things. About atmosphere and presence.

Lagom

Swedish philosophy of "just the right amount." Not too much, not too little. Perfectly balanced. Applies to everything from work-life balance to portion sizes. Moderation as a way of life.