Douglas warns, "If the market's behavior seems mysterious to you, it's because your own behavior is mysterious and unmanageable. You can't really determine what the market is likely to do next when you don't even know what you'll do next." 

Ultimately, "the one thing you can control is
yourself. As a trader, you have the power either to give yourself money or to give your money to other traders." 

He adds, 

"The traders who can make money consistently . . . approach trading from the perspective of a mental
discipline."
Each trader.

When you trade, you compete against the sharpest minds in the world.

The field on which you compete has been slanted to ensure your failure. 

If you allow your emotions to interfere with your trading, the battle is over.