We must recognize the psychology of the speculator militates strongly against the speculator. For by relation of cause and effect, he is most optimistic when prices are highest and most despondent when they are at bottom. Hence, in the nature of things, only the exceptional speculator can prove successful, and no one has a logical right to believe that he will succeed where most of his companions must fail.
– Benjamin Graham adn David L. Dodd, 1934