A banker who is allowed to borrow money at X and loan it out at X plus Y will just go crazy and do too much of it if the civilization doesn't have rules that prevent it.

There are two kinds of businesses: The first earns 12%, and you can take it out at the end of the year. The second earns 12%, but all the excess cash must be reinvested - there's never any cash. It reminds me of the guy who looks at all of his equipment and says, 'There's all of my profit.' We hate that kind of business.

I don't want to understand Facebook.

Obviously if you want to get good at something which is competitive, you have to think about it and practice a lot. You have to keep learning because world keeps changing and competitors keep learning. You have to go to bed wiser than you got up. As you try to master what you are trying to do – people who do that almost never fail utterly. Very few have ever failed with that approach. You may rise slowly, but you are sure to rise.

To the man with only a hammer, every problem looks like a nail.

This is a good life lesson: getting the right people into your system is the most important thing you can do.

We have a high moral responsibility to be rational