Using 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.
A lot of people with high IQs are terrible investors because they've got terrible temperaments. And that is why we say that having a certain kind of temperament is more important than brains. You need to keep raw irrational emotion under control. You need patience and discipline and an ability to take losses and adversity without going crazy. You need an ability to not be driven crazy by extreme success
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 first chance you have to avoid a loss from a foolish loan is by refusing to make it; there is no second chance.
And your brain doesn't naturally know how to think the way Zeckhauser knows how to play bridge. "for example," people do not react symmetrically to loss and gain. Well maybe a great bridge player like Zeckhauser does, but that's a trained response. Ordinary people, subconsciously affected by their inborn tendencies.
[GEICO] got to thinking that, because they were making a lot of money, they knew everything. And they suffered huge losses. All they had to do was to cut out all the folly and go back to the perfectly wonderful business that was lying there.
