I've always hated Valentine's Day. Always. Even when I was happily in relationships, so you can't attribute my hatred towards it to bitterness, like you can most every other aspect of my personality.
In lieu of writing my own, unfunny (read: bitter) rant against VD, I'll simply point you to GayProf, who has eloquently written his own loving tribute to that most Holy of Hated Days, on his blog, Center of Gravitas.
I'll let him speak for me, since he seems to do it quite well. (I like his last suggestion the best, in case anyone feels like treating me to a little Valentine's gift!)