Successful investors like stocks better when they’re going down. When you go to a department store or a supermarket, you like to buy merchandise on sale, but it doesn’t work that way in the stock market. In the stock market, people panic when stocks are going down, so they like them less when they should like them more. When prices go down, you shouldn’t panic, but it’s hard to control your emotions when you’re overextended, when you see your net worth drop in half and you worry that you won’t have enough money to pay for your kids’ college.

It's awful to have a depression, but it's a great thing to have a depression mentality because it means that we are not speculating, we are not living beyond our means, we don't quit our job to take a big risk because we know we might not get another job. There is something stable about a country, a society built on those values.

When you buy bargains and they become better bargains, it is easy to start to question yourself, which can impair your judgement. Real or imagined concerns about client redemptions, employee defections can greatly influence behavior away from rational.

There are only a few things investors can do to counteract risk: diversify adequately, hedge when appropriate, and invest with a margin of safety. It is a precisely because we do not and cannot know all the risks of an investment that we strive to invest at a discount. The bargain element helps to provide a cushion for when things go wrong.

Warren Buffett likes to say that the first rule of investing is "Don't lose money," and the second rule is, "Never forget the first rule." I too believe that avoiding loss should be the primary goal of every investor. This does not mean that investors should never incur the risk of any loss at all. Rather "don't lose money" means that over several years an investment portfolio should not be exposed to appreciable loss of principal.

One of the biggest challenges in investing is that the opportunity set available today is not the complete opportunity set that should be considered. Limiting your opportunity set to the one immediately at hand would be like limiting your spouse to the students you met in high school

Value investors will not invest in businesses that they cannot readily understand or ones they find excessively risky. Hence few value investors will own the shares of technology companies. Many also shun commercial banks, which they consider to have unanalyzable assets, as well as property and casualty insurance companies, which have both unanalyzable assets and liabilities.