Quote from ralph00:
Most underperform or get blown up because they are always playing. 99% of the time, trading is a negative expectation game and you will get ground down even faster than roulette at a casino. It's simply impossible to have an edge every day or every week (in the global macro game). Occassionally - maybe twice in a month, maybe twice in 18 months - a great trade comes along. Other than that, most would be better off on the golf course.
Fund managers are expected to be invested all the time and amatuers can't get away from the action or are trying to make up for losses. My greatest advantage (other than a damn keen intellect) is my ability to do absolutely nothing for long stretches of time. I can't remember the last time I've lost on a big trade that I waited and waited for. My losses all come from the need to be doing something.