1.They do not understand that the markets are a mirror of life on a chart. Markets are a living thing and reflect crowd behavior, the trader are one of the crowd too.
2.They fail to understand their own personality and what that means for their trading style.
3.They fail to notice how they transfer their feelings and emotions to their trading and believe that the emotions they pick up from other traders and the markets are theirs. Feelings are unpopular with traders, big mistake!
4.They have unresolved psychological blockages which they suppress with superficial positive thinking and learned discipline. We all have blocks, to think that you are the one who has not is dangerous arrogance.
5. And finally add to this one most important point for the beginning trader: Under capitalization due to unrealistic expectations and poor trader training. The recipe for trading failure is complete.