Ben Graham and Mr. Market:
Ben Graham long ago described the mental attitude toward market fluctuations that I believe to be most conducive to investment success. He said that you should imagine market quotations as coming from a remarkably accommodating fellow named Mr. Market who is your partner in a private business. Without fail, Mr. Market appears daily and names a price at which he will either buy your interest or sell you his. Even though the business that the two of you own may have economic characteristics that are stable, Mr. Market’s quotations will be anything but stable. For, it is sad to say, Mr. Market is a fellow who has incurable emotional problems. At times he falls euphoric and can see only the favorable factors affecting the business. When in that mood, he names a very high buy-sell price because he fears that you will snap up his interest and rob him of imminent gains. At other times he is depressed and can see nothing but trouble ahead for both the business and the world. On these occasions he will name a very low price, since he is terrified that you will unload your interest on him.