Confidence isn't the issue, its unjustified confidence and the actions made following. Some allow the arrogance of unjustified overconfidence to let them trade without a SL, trade without testing first the strategy, and so on. Ive met alot of traders in this industry, and the ones that usually have issues are the ones who are reckless with their accounts like a teenager first hitting puberty.
Pay attention to....is it confidence from a proven track record or arrogance? And someone stated above keep your professionalism which removes the emotions. The numbers dont lie....if you are not profitable you shouldnt be confident at your trading ability unless you are jsut trying to build commissions with your brokerr.