"Diversification is something that stock brokers came up with to protect themselves, so they wouldn't get sued [for making bad investment choices for clients]. Henry Ford never diversified, Bill Gates didn't diversify. The way to get rich is to put your eggs in one basket, but watch that basket very carefully. And make sure you have the right basket.
You can go broke diversifying. Ask anyone who's diversified in the last three years. They've lost money. Nonprofessionals are always jumping around, thinking they have to do something. If they have a big success, they think they need another one right away. That's when hubris sets in at its worst. That's when people really should go to the beach. It happens to me too."