Missing out on some opportunity never bothers us. What's wrong with someone getting a little richer than you? It's crazy to worry about this.

Fancy computers are engaging in legalized front-running. The profits are clearly coming from the rest of us - our college endowments and our pensions. Why is this legal? What the hell is the government thinking? It's like letting rats into a restaurant.

A lot of share-buying, not bargain-seeking, is designed to prop stock prices up. Thirty to 40 years ago, it was very profitable to look at companies that were aggressively buying their own shares. They were motivated simply to buy below what it was worth.

Intelligent people make decisions based on opportunity costs.

Berkshire's whole record has been achieved without paying one ounce of attention to the efficient market theory in its hard form. And not one ounce of attention to the descendants of that idea, which came out of academic economics and went into corporate finance and morphed into such obscenities as the capital asset pricing model, which we also paid no attention to. I think you'd have to believe in the tooth fairy to believe that you could easily outperform the market by seven-percentage points per annum just by investing in high volatility stocks.

In business we often find that the winning system goes almost ridiculously far in maximizing and or minimizing one or a few variables - like the discount warehouses of Costco.

The first chance you have to avoid a loss from a foolish loan is by refusing to make it; there is no second chance.