yes, i'm living proof that you can't win if that's all you try to do. for many years i felt i needed to win because i hated my job and i wanted a way out. i knew the more i won, the less time i'd have to be there. then when the debt from those losses began to mount, i felt i had to win because that was the only way to pay the debt and become net profitable. i had to avoid losses at all costs because that would be more debt and more psych. pressure.
in the end it broke me down to nothing. at least i can say how absolutely essential it is to not have that need-to-win mindset. i got caught a bit because usually i'm the type of person that does better under pressure (ie. tests, last-minute deadlines) but this was a scenario outside that realm, and the strategies that helped me succeed in other areas of life caused me to fail miserably in this arena.