The most important thing in terms of your circle of competence is not how large the area of it is, but how well you've defined the perimeter.
Warren BuffettIt's got to be the best intellectual exercise out there. You're seeing through new situations every ten minutes. In the stock market you don't base your decisions on what the market is doing, but on what you think is rational. Bridge is about weighing gain/loss ratios. You're doing calculations all the time.
Warren BuffettBut 300 million Americans, their lending institutions, their government, their media, all believed that house prices were going to go up consistently. And that got billed into a $20 trillion residential home market. Lending was done based on it, and everybody did a lot of foolish things.
Warren BuffettAnd people really behaved in a fraudulent way or something, we'll go back and find the culprits later on. But that really isn't the problem we have. I mean that's where it came from, though. We leveraged up and if you have a 20 percent fall in value of a $20 trillion asset, that's $4 trillion. And when $4 trillion lands - losses land in the wrong part of this economy, it can gum up the whole place.
Warren Buffett