Smart people learn from their mistakes. Smarter people learn from the mistakes of others. The smartest people learn from good advice. A pithy observation. Also, it would seem, good advice. No one learns solely from his own experience. If he tried, he’d ﬁnd life a lot more frustrating, and perhaps a lot shorter. All of us learn, for better or worse, by others’ guidance. The aim is to get better at separating good guidance from bad.