With so much money riding on reported numbers, human nature is to manipulate them. And with so many doing it, you get Serpico effects, where everyone rationalizes that it's okay because everyone else is doing it. It is always thus.

The normal expectancy of the average investor - for example, the pension funds of AT&T or IBM - is 6% for a long time.

Obviously if you want to get good at something which is competitive, you have to think about it and practice a lot. You have to keep learning because world keeps changing and competitors keep learning. You have to go to bed wiser than you got up. As you try to master what you are trying to do – people who do that almost never fail utterly. Very few have ever failed with that approach. You may rise slowly, but you are sure to rise.

All I want to know is where I’m going to die, so I’ll never go there

We regard using [a stock's] volatility as a measure of risk is nuts. Risk to us is 1) the risk of permanent loss of capital, or 2) the risk of inadequate return. Some great businesses have very volatile returns - for example, See's [a candy company owned by Berkshire] usually loses money in two quarters of each year - and some terrible businesses can have steady results.

The game of investing is one of making better predictions about the future than other people. How are you going to do that? One way is to limit your tries to areas of competence. If you try to predict the future of everything, you attempt too much.

... some important factor doesn't lose its "share of force" just because some "expert" can better measure other types of force.