Every person who has ever made a financial decision — wise or foolish — did so based on their own life experience. Someone who grew up during a depression thinks about cash and risk completely differently from someone who came of age during a bull market. Neither is irrational; they're each responding logically to the world they personally witnessed.

Morgan Housel's central observation is that we all believe we understand how money works, yet we each have a radically different dataset. The person who hoards cash under a mattress and the person who pours everything into equities are both making sense — given what they've personally seen and felt.

This means judging other people's financial behaviour as 'crazy' is almost always a mistake. What looks reckless or timid from the outside is usually a reasonable response to that person's lived history. Understanding this is the first step toward financial empathy — and toward examining your own blind spots.