The Core Idea
Your brain has two modes: System 1 (fast, intuitive, automatic) and System 2 (slow, deliberate, effortful). Most of the time you think you’re using System 2, but you’re actually running on System 1 autopilot — and it’s full of predictable biases.
What Stuck With Me
The anchoring effect is wild. Completely arbitrary numbers influence our estimates even when we know they’re arbitrary. It makes you question every “gut feeling” you’ve ever had about pricing, time estimates, or probability.
The planning fallacy chapter should be required reading for anyone who manages projects. We are systematically terrible at estimating how long things will take, and knowing about the bias doesn’t fully fix it.
Who Should Read This
Anyone who makes decisions (so, everyone). It’s long and sometimes academic, but the insights compound. I found myself noticing my own cognitive shortcuts for weeks after finishing it.
Not a quick read — budget time and take notes.