Those who come to market for only hedonism will have high probability to fail. Don't come to market if it is for proving anything to yourself. Only prove your system not yourself because if your system is not proof-safe then it is not worth trading it is only gambling. Those who have "psychological" problem are those who can't stick to prove and improve their system but challenge themselves about their psy: that's what they are brainwashed all day long by psy gurus. Of course psychology counts but your psychological behavior is the consequences of lack of focus on the stuff that really matters: winning money by being consistent not satisfy your intellectual pleasure. By system I don't mean mechanical system here I rather mean framework so that it applies even to discretionary trader.