It all seems so easy, just buy low and sell high (or sell high and buy low). So how come so many people do the exact opposite? From doug Casey at internationalman.com:
Why is assessing the psychology of the market so important?
Doug Casey: The market, as Warren Buffett has pointed out, can be either a weighing machine or a voting machine. You can make money in the market either way, but you have to recognize which machine is giving you signals.
Although Mr. Market sees and knows almost everything, he pays the most attention to the voting machine, because he’s basically bipolar, a manic-depressive. As a result, not only do you have to deal with the psychological aberrations of millions of other people who are running in a crowd and voting with their dollars, but much more important, you have to deal with your own psychology. You are, after all, part of the market.
The only thing you can control, however, is your own psychology, not that of the market’s other participants. Once again quoting Buffett, “Be fearful when others are greedy. Be greedy when others are fearful.”
It’s a matter of having good psychological judgment. Everybody wants to be a contrarian, and perhaps they think they are a contrarian. But, in reality, it’s hard to be a contrarian.