"There isn't much point to making a lot of money if you are susceptible to making that one trading error that can give it all back plus more. Once you have made a fortune and lost it, the psychological work that you will need to do to get it back is enormous compared to work that is necessary to keep yourself from losing it in the first place. As a trader it is more important to know that you will always follow your rules than it is to make money, because whatever money you make, you will inevitably lose back to the market if you can't follow your rules."
Mark Douglas - The Disciplined Trader
Futures & Options Broker