Psychology is a very important passive tool for a trader. It is detrimental to the success or failure of one.
I say so because as a full-time trader without much experience I go through some bout of anxiety related to trading every day. To tame it I take frequent breaks. Should you wish for a run-through of my trading journey, please be my guest.
For amateurish mistakes, I cater as well because this is also a learning journey for me.
Hope these serve to cement the notion that study of the subject and control on emotions are exceedingly important.