Arrogance doesn't make you a bad programmer. It, in general, makes you a person that others don't like to be around. And if you want to get hired by a large company, likability is part of the package. Not because it's a popularity contest, but because those other people there will need to spend 8 hours every week day with you.

I know your story - I've not been exactly popular in HS either. I did not excel at quite a few thing. Like you, for a while I thought I could gain more confidence by loudly proclaiming my superiority when I actually was better at things than my peers.

All that creates is resentment. The best piece of advice I ever got - and it might well be meaningless to you, but let me share anyways - was that "Actions speak louder than words".

Go forth, do great stuff. Help other people achieve greatness. Be judicious when you do and don't mention your achievements. (I'm not saying to never toot your horn, but do it by choice, to make a salient point). And never, ever, call yourself "great". There are few truly greats in any profession. Aspire to be one. You'll know you're there once others refer to you by that label.