In fact I've probably never seen such a wide moat.

An investment decision in the common stock of a company frequently involves a whole lot of factors interacting ... the one thing that causes the most trouble is when you combine a bunch of these together, you get this lollapalooza effect.

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.

I regard the amount of brainpower going into money management as a national scandal. When some idiot would get rich, they'd say, 'Well, old Charlie was out in the field playing the big brass tuba on the day it rained gold.' A lot of people have become rich lately who were playing the tuba on the day it rained gold.

Warren spends 70 hours a week thinking about investing .

Learn how to ignore the examples from others when they are wrong, because few skills are more worth having.

Avoid evil, particularly if they're attractive members of the opposite sex.