Addiction. Belief that you can control the outcome on a moment by moment basis. Paying too much attention to the movement rather than the waves. I so far was able to build up to 4 funded accounts, but now I have 3 remaining, 1 with 300 drawdown, 200, and 2000.
To be a great trader, you have to have the capacity to take large amounts of stress and pain - frequently and repeatedly. You must get used to the pain, or feel the pain incessantly but continue to execute in the opposite reaction of human beings. When things go your