Mood or psychology is irrelevant. Only a profitable system will make you profitable.
Example: if warrent buffett had a great investor psychology but had a losing system of selecting his stocks, then no matter how psychologically grounded he is, he will make a loss over the long-term.
Another example: playing roulette in the casino. Odds are always against you, no matter how grounded your psychology is, you will always lose, cause there is no profitable strategy to beat the house