"Mr. Market, a fellow who turns up every day at the stock holder's door offering to buy or sell his shares at a different price. Often, the price quoted by Mr. Market seems plausible, but often it is ridiculous. The investor is free to either agree with his quoted price and trade with him, or to ignore him completely. Mr. Market doesn't mind this, and will be back the following day to quote another price. The point is that the investor should not regard the whims of Mr. Market as determining the value of the shares that the investor owns. He should profit from market folly rather than participate in it. The investor is best off concentrating on the real life performance of his companies and receiving dividends, rather than being too concerned with Mr. Market's often irrational behavior." -Benjamin Graham