It never ceases to amaze me to see how much territory can be grasped if one merely masters and consistently uses all the obvious and easily learned principles.

Opportunity cost is a huge filter in life. If you've got two suitors who are really eager to have you and one is way the hell better than the other, you do not have to spend much time with the other. And that's the way we filter out buying opportunities.

When I run into a paradox I think either I'm a total horse's ass to have gotten to this point, or I'm fruitfully near the edge of my discipline. It adds excitement to life to wonder which it is.

A lot of people with high IQs are terrible investors because they've got terrible temperaments. And that is why we say that having a certain kind of temperament is more important than brains. You need to keep raw irrational emotion under control. You need patience and discipline and an ability to take losses and adversity without going crazy. You need an ability to not be driven crazy by extreme success

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.

Of course the self-serving bias is something you want to get out of yourself. Thinking that what's good for you is good for the wider civilization and rationalizing all these ridiculous conclusions based on this subconscious tendency to serve one's self is a terribly inaccurate way to think.

A different set of incentives from rising in an economic establishment where the rewards system, again, the reinforcement, comes from being a truffle hound. That's what Jacob Viner, the great economist called it: the truffle hound - an animal so bred and trained for one narrow purpose that he wasn't much good at anything else, and that is the reward system in a lot of academic departments.