Breaking the nail-biting habit

SINCE my childhood days, I have always bitten my nails. It is a bad habit and I’ve been chided often by grown-ups and toddlers alike. Not only does nail-biting mean stubby fingers without the graceful display of groomed nails, it is also without doubt unhygienic and frankly, quite gross. I know all of the facts, so why do I keep nibbling away?