In response to a question on how to control emotions in investment:
“… You have to have the right temperament. I tell the students who come visit me that if you have more than 120 or 130 I.Q. points, you can afford to give the rest away. You don’t need extraordinary intelligence to succeed as an investor. You need a philosophy and the ability to think independently…It doesn’t make any difference what other people think of a stock. What matters is whether you know enough to evaluate the business,” he opined.
“You should be able to write down on a yellow sheet of paper, ‘I’m buying General Motors at $22, and GM has  million shares for a total market value of $13 billion, and GM is worth a lot more than $13 billion because _______________.” And if you can’t finish that sentence, then you don’t buy the stock. [Note: Buffett mentioned GM for illustrative purposes only.] All this requires some temperamental detachment from other people’s behavior. Both Charlie and I have a natural instinct in that direction. We value our opinions more than others’ — perhaps to an extreme!”