Self-confidence or self-critical ?

on Monday accidentally had longer than usually talk with one acquintance/kind of uni friend. As usually girl gab and loughts But one thought of her I remember clearly, she said that she don't let her go down - everyday she criticize herself for many things. That's how she reach best for her. At that moment I just tried to show her other side of this and give few arguments in reverse idea. However at evening this her saying give me a loot of thought. Maybe really men can reach more with criticism? Not so long time ago I begun to believe and trust on my self, even become more than 100% self confident (that's why always at skype into compliments answer - I know). I really was deep into believing that's what person need to reach they aim - self confidence.whatever it is - trip to Paris, studies in foreign, learn more than 4 languages, have a perfect husband. So maybe just because of I wasn't trust on myself recently seventeen years, I cant accept that idea so easy? Or is a big question for "normal" people too?
Is person who are self-confident or self-critical can reach more in life?
and now that talk with my study friend hit my persuasions. She really gives me reason reconstruct believes in my head. Besides for warning I want to mention she is not senescent of grey personality or just all the time sitting near books, yes her marks are good and just very good, she is very tolerant and calm girl, well not really interesting in fashion or style things, but active as a student, communicative, maybe more than me,even I pretend are very communicative. So I guess she is kind self confidence inside, just instead demonstrating it she choose harder(?) way -every day look for her mistakes, for her own faults and incorrect in her eyes her behave. Is that type of personality's aren't in bigger risk to let them down and completely loose self esteem. I imagined that I would get overcrtisice myself in such way and than wont be able to even think about my aims, not talking about trying to reach them. Maybe time to let go this persuasion. Do a circle? When was teenager every day hate myself and criticize, than finally let that go that crap and grown up a little with self esteem and more trust on what I doing, now, when talkin about bigger purposes than just growing alive, have come back to self-criticism. Is really for to reach what I want I have every time look for faults, mistakes errors in me, in myself?I don't say I never does. Just not so often and not so cruel few days contemplation I left at harmony. I don't want to ruin my so hard and long builted self esteem, but with more response I will try to look for faults in my business, in other words - not personal life.