I am not so sure that overtrading is so much the frenzy for quick money as it is the fear of losing out on trades that appear that others are probably making money on successfully. In all endeavors people hate to be the one who gets left behind. It is a natural reaction. However, in trading this creates what I call "impulse" traders. They do not think in probabilities, nor do they practice and excel in a few set-ups or wait patiently for their set-ups.
They see what appears to be a big move starting and they are off to the races. As we all know, they had no other reason for taking those trades other than a feeling or seeing the line on the chart moving up without them, etc.
As to cold and unemotional traders... there simply is no such animal. The professionals are simply in far better control of the emotions that hit them in the heat of the trade and even the best of them succumb to a little too much exuberance on occasion that snares some of their dandy profits. Don't ever fool yourself into thinking otherwise and try to force yourself to become this totally emotionless trading robot. You will never get to that stage and will always be thinking those other guys must somehow be a little more or less than human.
Happy Trading
