Damn thin lines

What do you call someone who thinks he is really-really good in something? "One who has his nose high up, and a big idea of himself", or "one who is passionate enough about something and rightly believes he can produce something extraordinary if he really gets his butt down to working on it"? What do you call someone who deep down believes he is really-really good in something, but is never satisfied with the outcome of his efforts? "One who should finally listen to that little voice that keeps trying to bring him back to planet earth, make him see the disappointing reality", or "one who simply needs to hang in there, keep believing in himself, for in the end he will be proven right"? And what do you call someone who, after struggling with himself for a long time, finally accepts he's no special, he's not, after all, that good in what he thought he was good at? "A wise guy who finally let go of his mega ego and can now enjoy his little every day -but not extraordinary- talent in something, just for the fun of it", or "a pathetic loser who lacks self-confidence and deserves to live the rest of his life with the torturing thought 'what if I had a little more faith in me'"? If you ask me, the lines are damn thin, and this comes with... a good deal of anxiety and excitement, if you think about it... It's like applying for a dream job, for example. You file in your application, and you wait to hear from your potential employer. Waiting for your phone to ring, you think about the best case scenario, and also about the worst case scenario, one moment you dream of getting the job, next moment you feel you are free-falling and there's no safety net to ease your landing... Until the moment you hear the news, you are free to dream, and... who knows, maybe your dream will come true... If not, you patch up your broken wings, and take your time before trying again, no?...
Hm... These last ten days, after losing my job, I have been spending 23 hours a day alone, over-analyzing stuff in my mind. Not necessarily the best possible thing someone could do, right? Right...