There was a time when I'd have happily soaked up that sort of comment; rolled with it, encouraged it. The honest truth is, I've spent a lot of, if not most of, my life... well, I suppose "desperately insecure in the midst of palpable security" would be an interesting way to put it. It's a salve to emotional wounds to use your strengths to try to impress people, thus propping up the weaknesses you're curled around - rather than using your strengths intelligently, to build things. I've applied way too much of that salve, over the years. I don't want to do it anymore.
So, yeah, what about the real answer to the bewildered (or even annoyed) question "why are you in college again?" It's too long and involved to respond with in casual conversation, but I can give it here, even if the folks who ask it will never see it: Because it represents opportunity. Because I am taking the opportunity to really learn things. Because, no matter how it may look to a hapless newbie taking a programming class side-by-side with me - no matter how much of a joker in the deck I may be in a class like that - I do get a lot out of it. Because I genuinely enjoy it. Because it makes me feel better about myself. And last, though probably not least, simply because I can.