"Will you stop biting your nails!" Every kid has heard that at some time or another. But it's just downright annoying when the habit goes on and on, regardless of the number of times you decide to stop. Without even noticing you're doing it, you absent-mindedly chew those nails back into that ugly, painful condition again. And that's the whole problem: the nail biting is unconscious, you do it without even noticing. So when you make a conscious decision to stop nail biting, nothing happens as the cure has to happen at a subconscious level.