You'll better understand the evil when top audit firms started selling fraudulent tax shelters when I tell you that one told me that they're better [than the others] because they only sold [the schemes] to their top-20 clients, so no-one would notice.

Black-Scholes is a know-nothing system. If you know nothing about value - only price - then Black-Scholes is a pretty good guess at what a 90-day option might be worth. But the minute you get into longer periods of time, it's crazy to get into Black-Scholes. For example, at Costco we issued stock options with strike prices of $30 and $60, and Black-Scholes valued the $60 ones higher. This is insane.

It would be easier to screw up American Express than Coke or Gillette, but it's an immensely strong business.

The investment game is getting more and more competitive.

Almost all good businesses engage in 'pain today, gain tomorrow' activities.

You must have the confidence to override people with more credentials than you whose cognition is impaired by incentive-caused bias or some similar psychological force that is obviously present. But there are also cases where you have to recognize that you have no wisdom to add - and that your best course is to trust some expert.

To finish first you have to first finish. Don't get in a position where you go back to go. What's interesting is that some guy whose grandfather was a lawyer and a judge-hurriedly going to Harvard Law with a wave of veterans-I was willing to go into so many different businesses. I was constantly going right into the other fellow's business and doing better than the other fellow did. The reason it was possible? Self-education- developing mental discipline, big ideas that really work.