Even the most successful traders make costly mistakes constantly. After all, it's just part of the game we've decided to play. Traders are forced to make hundreds of critical decisions every day. Inevitably, many of them turn out to be complete bummers.

All of us have thrown away fortunes over the years because of mental errors. These gaffes run the gamut from cerebral lapses to misguided opinions. Not surprisingly, the most common mistakes cause the most damage. For example, how much money did you lose chasing the upside during the bear market?

Trading mistakes can't be eliminated, but we can reduce their negative influence. Start by listening to the little voice in your head. Let it question every decision you make. Soon you'll find a dozen ways you're losing money for no reason.

I've compiled a list of 10 onerous trading mistakes. This confessional comes from my own experience. Yes, I admit falling prey to every one of these from time to time.

• Fighting Mr. Market. There's nothing worse than trading a trend in a choppy market or sideways choppiness in a trending market. Make sure you know which one you're jumping into before hitting the enter button.
• Loving the bad. It's hard to admit it when we're wrong. Rather than cutting losses, we try desperately to transform our worst trades from lemons into lemonade. Sooner or later we find out how easy it is to turn a small loss into an absolute disaster.
• Hating the good. Sometimes we know it's a great trade, but only at the subconscious level. For some reason, we can't handle our good fortune and jump out with a small profit. Minutes later it takes off like a rocket ship without us on board.