The cashier, the coach, the cousin you ignore at holidays. Each one knows something you’d pay to learn.

Expertise is distributed far more evenly than status is. Everyone who has done anything for a while knows things that are written down nowhere, and the person you mentally file as ordinary is usually the expert on something you know nothing about. The barrier is not access, it is that nobody asks.

Ask one person you see regularly what most people get wrong about what they do. Then stay quiet long enough for the real answer. You will learn something, and you will also change the temperature of that relationship.