""I can give you the best rules in the world and the best methods for determining the position of a commodity, and then you can lose money on account of the human element, which is your greatest weakness. You will fail to follow rules. You will act on hope or fear instead of facts. You will delay. You will become impatient. You will act too quickly or you will delay too long in acting, thus beating yourself on account of your human weakness, then blaming it on the market. Remember that it is your mistakes that cause losses and not the action of the market or the manipulators. Therefore, strive to follow rules, or keep out of speculation, for you are doomed to failure"

W.D Gann in How to Make Profits in Commodities