Most people think they’re better than the average person: that they’re smarter, more likeable, more attractive. This tendency to think of ourselves as better than average is a well-established bias. But if we need to do this to feel better about ourselves, who cares? The problem is that we’ll also overestimate our chances of being successful. And if you want to work out where to make the most difference, you need to have a realistic idea of where your chances of success are best.