Clear Thinking: What I Learnt About Systems for Hard Days
Some of our worst decisions don’t happen because we’re unintelligent — they happen because we’re tired, emotional, distracted, or under pressure.
I’ve noticed this in my own life too: when I’m rested, calm, and in a good headspace, it’s easy to think clearly. But when I’m running on fumes or stuck in reactive mode, that’s when overreactions or plain avoidance start to creep in.
Clear Thinking by Shane Parrish felt like a manual for closing that gap. It’s about creating systems, habits, and safeguards when you’re at your best — so they still work for you when you’re not. It’s not about perfection. It’s about making it harder to slide into poor choices, and easier to keep moving in the right direction.
The book is full of practical guardrails, simple mental models, and good questions — the kind you can actually use in the middle of real life, not just in theory. And it reminded me that the best time to set yourself up for good choices is before you need them.
What Clear Thinking Is Really About
At its core, Clear Thinking is about decision design. It’s not about becoming perfectly rational — it’s about recognising that you won’t always be. The book teaches you how to think ahead on your good days so that your systems protect you on the bad ones.
Key Concepts in Clear Thinking That Stuck
You can’t count on always feeling sharp, patient, or objective — but you can design conditions that help you make better decisions more often.
The shift is simple but powerful: instead of relying on willpower to get you through tough moments, build systems that will catch you when you’re tired, stressed, or tempted to do a quick fix.
Here are the ideas from the book that resonate most with me right now — the ones I can already see shaping how I work, decide, and move through daily life.
Concept #1: Self-confidence is focusing on what’s right, not who’s right
It’s easy to get caught up in proving ourselves, defending our opinions, or “winning” the conversation. Shane reframes confidence as the ability to set ego aside and zero in on what’s true and useful, regardless of where the idea comes from. It’s not about being the smartest voice in the room, but about creating the conditions for the best ideas to win.
Concept #2: Ask: “Will this make the future easier or harder?”
This might be the simplest (and most useful) decision-making filter in the whole book. Before you act, pause and ask yourself this question. It forces you to zoom out from the immediate situation and consider the ripple effects. Sometimes what feels easier in the moment (avoiding a tough conversation, saying something out of anger, going for a quick fix) will make life much harder later.
On the flip side, the harder choice right now — like setting a boundary, slowing down to check your work, or saying “no” — might make everything smoother down the road.
Concept #3: Use HALT before making big decisions
Hungry. Angry. Lonely. Tired.
These four states are a breeding ground for poor judgment. The HALT method is a quick self-check before making important decisions: Am I in one of these states right now? If the answer is yes, it’s worth delaying the decision (if possible) until you’re in a better state to think clearly.
Concept #4: Separate problem-defining and problem-solving
One of the fastest ways to waste time is to solve the wrong problem. Shane suggests splitting these into two separate meetings:
One to clearly define the problem.
Another (later) to brainstorm solutions.
This extra pause prevents you from spending energy on the perfect solution… to the wrong thing.
Concept #5: Test of Time
Before committing to a solution, ask: “Will this fix the problem permanently, or will it come back?” If the latter, you’re probably treating a symptom.
It’s tempting to go for the quick fix — it feels satisfying in the moment and gets the issue off your plate. But quick fixes often have a way of circling back, sometimes bigger than before. The Test of Time pushes you to slow down, dig deeper, and solve the real problem, even if it takes longer. The payoff? You stop fighting the same fires over and over.
Concept #6: Three Principles to Know When to Stop Deliberating and Start Acting
These are three quick rules to help you know when to act:
ASAP: If the cost to undo a decision is low, decide quickly and learn by doing.
ALAP: If the cost to undo is high, wait until the last responsible moment.
Stop-Flop-Know: Stop when you’ve gathered enough information, when you’ve missed a clear opportunity (flop), or when you suddenly know the right choice.
Concept #7: Opportunity cost isn’t just about money
Borrowing from Charlie Munger, Shane reminds us that smart decisions aren’t made by looking only at what you’ll gain — you have to also consider what you’ll give up by saying yes. That trade-off could be time, focus, or another opportunity you’ll now have to pass on. Keeping opportunity cost in mind makes decisions more grounded in reality.
Why I’m Glad I Read This
I picked up Clear Thinking at a time when my decision-making bandwidth felt… thin.
Work was full, life was full, and even small choices felt heavier than they should.
Shane’s approach landed because it wasn’t about “try harder” — it was about set yourself up better. It gave me practical guardrails I could put in place on a good day that would still catch me on a bad one.
It also reminded me that decision-making isn’t just about being smart — it’s about designing conditions where good choices are the path of least resistance. That felt like a relief.
How I’m Applying This
Personally
Pause before reacting — I now check in with myself first: Am I hungry, angry, lonely, or tired? (HALT). It sounds simple, but this quick scan has stopped me from sending reactive messages or saying yes when I’m running on empty.
Ask: “Will this make the future easier or harder?” — I use this question a lot in communication. It reminds me that being “right” isn’t always the goal — sometimes, what really matters is keeping a conversation open and constructive.
Professionally
Design systems that save future-me time — We’ve started building processes (like custom GPTs for content writing) that reduce repetitive work. It’s freed up mental space and made collaboration feel smoother and lighter.
Decide quickly when the stakes are low — I used to ruminate over small choices — design tweaks, email replies, small project details. Now, I lean on the ASAP principle: decide fast, adjust later. It’s made work flow with less friction.
Focus on what’s right, not who’s right — This one has softened how I handle feedback and client discussions. I’ve learned to pause before defending my point and instead ask, “What outcome are we both trying to achieve?” It shifts the conversation from being about ego to being about alignment — and things move forward faster when everyone feels heard.
Mindset Reframes for Clearer Thinking
We’re all making decisions every single day — from the small and mundane to the ones that shape our work and lives. I’ve realised that having a handful of simple mental models is like carrying a decision-making toolkit. It lightens the mental load, reduces second-guessing, and helps me avoid the kind of fatigue that leads to poor choices.
From: “I need to make the perfect decision now.”
To: “I just need to make the best decision for this moment — with what I know.”
From: “I’ll handle it when it happens.”
To: “I’ll design a system now so future-me has an easier job.”
From: “If I try harder, I’ll make better choices.”
To: “If I think ahead, I’ll make better choices — even on hard days.”
If This Resonates, Try This
If you’ve ever caught yourself making quick decisions you later question — or overthinking ones that shouldn’t take that long — these ideas from Clear Thinking are a good place to start.
Use the HALT check before reacting. Ask yourself: Am I hungry, angry, lonely, or tired? Most bad calls come from one of these four states.
Ask: “Will this make the future easier or harder?” next time you’re unsure what to do. It’s a surprisingly grounding filter.
Separate the problem from the solution. Spend one conversation defining what’s actually broken — and another fixing it.
Decide fast when the stakes are low. Not everything needs a pro-con list. Try the ASAP principle: make the call, learn from it, move on.
Design one system that supports future-you. Whether it’s a checklist, a shared folder, or a simple note template — small structure, big clarity.
The goal isn’t to be perfectly rational all the time — it’s to make it easier to be clear when it matters most.
Who I’d Recommend Clear Thinking To
For anyone who’s ever looked back at a decision and thought, “What was I thinking?”
It’s especially valuable if you:
Make lots of decisions under pressure (leaders, founders, creatives, parents — honestly, all of us)
Want to reduce decision fatigue and second-guessing
Tend to default to short-term fixes instead of lasting solutions
Want simple, repeatable tools you can use even when you’re tired or distracted
If you want clearer thinking without adding noise or complexity, this one’s worth your time.
Who This Book Might Not Be For
If you’re looking for:
A quick-fix formula — This isn’t “five steps to perfect decisions.”
Deep theory — Shane keeps it practical and actionable.
Instant results — The magic is in applying it over time, not skimming once.
This book won’t make you perfectly rational overnight. But it will help you recover faster when you’re not.
Closing Thoughts
Clear Thinking reminded me that clarity isn’t about knowing all the answers — it’s about creating the conditions to see more clearly when things get messy.
We’ll always have moments where we react, rush, or get it wrong. But when you design systems that support your better self, you spend less time course-correcting and more time moving in the right direction.
That’s what this book really taught me: thinking clearly isn’t about being calm all the time — it’s about building enough self-awareness and structure so you can recover faster when you’re not.
If you’ve enjoyed this book note and want to explore more, we’ve shared why we’re starting a book notes series — along with a growing library of reflections on the books that are shaping how we think, work, and live.
Thank you for reading and learning with us!
