Most people, in fact an estimated 3/4 of the population, think of introverts as antisocial, conceited, stuck-up, and as individuals who just don't like other people in general. This is very far from the truth. Rather than try to explain it all here, I encourage anyone who thinks they know an introvert to read this article... it's very enlightening: http://www.theatlantic.com/magazine/archive/2003/03/caring-for-your-introvert/2696/
I really do WANT to like doing things with other people, but it's truly exhausting sometimes. It's shocked me every single time I find out someone thinks I'm stuck-up. For one thing, they couldn't be any further from the truth (I really don't think all that highly of myself), and for another, I despise people who are stuck upon themselves, and for someone to think I'm in that category just blows me away.
But in the last year, I've taken some wonderful classes in biology. I've been meeting people a lot like myself: science/biology geeks who have some degree of social ineptness. Going to class is definitely a 'group activity', but I rarely find it exhausting. In the last few months, I've actually come home feeling invigorated. I'm more willing to put in volunteer time, participate in study groups, and help tutor. I never would have entertained doing these things a year or more ago.
It's nice to feel this way, when I never have before. It reaffirms my decision to go forward in getting an education and go for at least a Master's.