I bite my finger nails. I'm not sure why, I just started doing it one day, and I can't stop. Its an addiction for me. I recently stopped for about a month. Even though I would not bite them, I would always run my nail over my tooth, especially when they got normal length (some coming over the bed of the nail). Eventually, I bit one off, and then another...and now i'm back to biting them again. I don't bite them bad like some people, though I have occasionally bit a couple till they've bled on accident. My hands look normal, you probably wouldnt' be able to tell that I bite them. You'd think I just clipped them a little short.