correct mindset for piano playing

have found that many of the mistakes have a common root cause: my mindset for piano playing, be that in practice and that on the stage as well, particularly the latter..
what did i have in mind, consciously or unconsciously, when i was at the stage? if that primarily to prove myself, was that working for the better or worse? if worse, was that a wrong motive to have? if in itself it was not, how could i take advantage of that? need to nail down on it. The strong hypothesis is twofolds: (1) lack or shotage of understanding what exactly i should / want to do, and (2) attempting to do way more than i can do. if this is correct, the countermeasures would be extremely simple; to squarely face my weaknesses (and strengths) and mobilize my full brain potential to do the right things at every moment of practice with full concentration on well thought-out practice plan. There is no trick or shortcut. No room for wishful thinking. Never overestimate or underestimate your ability. Never be distracted by what others do. Never ever force things. Just be yourself, be natural and fluid.