I have about a thousand reasons, but I'll only list a few...
1) I don't get out a whole lot.
2) When I do get out, I'm too shy to talk to people.
3) When I talk, people always comment on how monotone my voice is, which pisses me off to the point of telling them to fuck off.
4) I'm a very impatient person, which often results in #4.
5) Even though I'm in high school (senior), I don't like high school girls. However, despite the fact that I like older women, older women don't take me seriously.
6) I'm generally 'too whiny' for most women.
7) I still live with my parents.
8) Too cheap for a girlfriend. (Read: no money, no job)
9) I've pretty much just stopped trying.