My bad habit is nail biting i know This can damage our teeth as well as the skin around our nail bed, which can lead to infection.I also may get more colds and other illnesses when i put our fingers, which often carry germs, into our mouth. It can help to keep our nails neatly trimmed or manicured. If stress could be the reason for our habit, i knw this is not good is my health i can't leave.