Morgan Housel opens with a striking idea: no one is crazy when it comes to money. Every financial decision a person makes — no matter how irrational it looks from the outside — is shaped by their unique life experiences, the era they grew up in, and the lessons their environment taught them. A person who lived through the Great Depression has a completely different relationship with risk than someone who entered the workforce during a bull market. Neither is objectively right or wrong; they are simply responding to the world as they have experienced it.

This is the book's foundational insight: personal finance is deeply personal. Because we all have different financial histories, we will inevitably disagree about how to spend, save, and invest. Judging others' money choices without understanding their backstory is like criticising someone for fearing the dark when you've never experienced a blackout. The first step toward financial wisdom is recognising that your own perspective is shaped by factors outside your control — and so is everyone else's.