Just being with one for a while will show you that bias very quickly when you hear about how every random person they passed on the street secretly hates them or thinks they're ugly or somehow did something that relates to their biggest insecurity.

It's true that I can't prove the world doesn't secretly hate them, but my own experience of literally never thinking about the random strangers I walk past informs my belief that this likely has more to do with the person's insecurity than the reality of what's going on in those people's minds.