Nail biting is a common symptom of stress among children and adolescents, as well as a frequent manifestation of obsessive-compulsive disorder. A Dutch therapist thinks he has the solution and has successfully treated about 150 customers with a method that includes a mouth guard that inhibits biting. The guard can be removed to eat. He says his treatment program is so successful that he's added manicurists' chairs to his office to help his clients bring their newly growing nails back to health. At about $670 U.S., I think I'd appreciate a manicure along with my treatment!

All kidding aside, obsessive nail biting can be a socially isolating problem. If you think your habit isn't bad enough to commit to therapy, check out these DIY tips for quitting your nail biting habit.