Bull markets go to people's heads. If you're a duck on a pond, and it's rising due to a downpour, you start going up in the world. But you think it's you, not the pond.

You need a different checklist and different mental models for different companies. I can never make it easy by saying, 'Here are three things.' You have to derive it yourself to ingrain it in your head for the rest of your life.

I don't invest in what I don't understand. And I don't want to understand Facebook.

If the value of a company doesn't just scream out at you, it's too close.

If you always tell people why, they'll understand it better, they'll consider it more important, and they'll be more likely to comply.

In my life there are not that many questions I can't properly deal with using my $40 adding machine and dog-eared compound interest table.

If you have only a little capital and are young today, there are fewer opportunities than when I was young. Back then, we had just come out of a depression. Capitalism was a bad word. There had been abuses in the 1920s. A joke going around then was the guy who said, 'I bought stock for my old age and it worked - in six months, I feel like an old man!' "It's tougher for you, but that doesn't mean you won't do well - it just may take more time. But what the heck, you may live longer."