Trading and self-discipline.

The one thing I can think of that most affects both trading and investing has to be self-discipline.

Being disciplined is fully 50% of the job of trading or of investing. I don't care how good your trading system is, without the discipline needed to follow the system you don't have much of a chance for success in meeting your goals.

It doesn't matter how great a planner or organizer you are, without discipline your plans will most likely fail to bear fruit.

I agree 100% with the following statement by Marty Schwartz, the great S&P 500 daytrader:

"I've said it before, and I'm going to say it again, because it cannot be overemphasized - the most important change in my trading career occurred when I learned to DIVORCE MY EGO FROM THE TRADE. Trading is a psychological game. Most people think that they're playing against the market, but the market doesn't care. You're really playing against yourself. You have to stop trying to will things to happen in order to prove that you're right. Listen only to what the market is telling you now. Forget what you thought it was telling you five minutes ago. The sole objective of trading is not to prove you're right, but to hear the cash register ring."

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