I don't really know. I've always enjoyed learning about new things and trying to explain them to other people, but life sort of gets in the way of doing that full time. Between loving being a teaching assistant for introductory computer science courses and having profs (especially in math) that left me thinking "Hey, I could teach this better", I think it was university that made me realize that deep down, teaching others is a passion of mine.

Of course, that's not at all what I'm doing now, and I'm not even on track to teaching as a career and don't know when I will be. It's okay though. That's just how life works. I work a job I often enjoy with people I like, and I'm slowly working towards building a website where I can just brain-dump all the cool stuff I know, so hopefully I'll get more fulfillment with that.

I guess I don't really have any advice for you other than to keep learning. You don't know what you're passionate about, but you're probably passionate about something. The answer is out there somewhere, and you just have to find it. Don't expect it to hit you like a lightning bolt. I mean, it could, who am I to say? But it might be that you just have to pick something that's mildly interesting to you and work at it for a while. Passion comes with time. Learn to play an instrument or solve a Rubiks cube or juggle or memorize PI to 100 decimal places, or all of those things. Volunteer with some organization that's mildly interesting to you. Just keep doing things and you'll find it.

Also, screw talent. I play a few instruments (most very poorly, some averagely, in my mind). People think I'm talented. They don't see the amount of time I've put into learning them, and they don't know that it feels like trying to make a hole in a wall by bashing your head against it. Sure, talent helps, it'll get you there faster, but not giving up is much more important.

Sorry if this is kind of rambling. It's been a long day and I'm tired.

tl;dr: Keep learning. Don't quit. Try new things. Stay humble.