I began to develop what I thought was an indicator of whether someone was going to be a good surgeon or not. It was a couple of simple questions: Have you ever made a mistake? And, if so, what was your worst mistake? The people who said, 'Gee, I haven't really had one,' or, 'I've had a couple of bad outcomes but they were due to things outside my control'—invariably those were the worst candidates. And the residents who said, 'I make mistakes all the time. There was this horrible thing that happened just yesterday and here's what it was.' They were the best. They had the ability to rethink everything that they'd done and imagine how they might have done it differently."