Chad Orzel, over at Uncertainty Principles, has invited readers to submit their "worst reason for being an atheist". The responses range from clever, to insightful, to self-disclosing. You can see them all (and add your own) here, but my top ten, with minor edits, are below:

1. To spite my Christian parents.
2. To spite God.
3. Because Madalyn Murray O'Hair was such a hottie.
4. Because my parents are atheists.
5. Because Ann Coulter isn't.
6. To fit in.
7. Because of what happened to Bambi's mother.
8. Because it's so darn hard to choose between Thor, Zeus and the rest of the gods.
9. Because Pascal was giving good odds.
10. Because you created the universe, but you forgot how, and are now in denial.

I also like Orzel's own reason, which  was "Chicks dig it."