My bad habit.

So i have had this bad habit since i can remember, and i have yet to figure out how to break it. Biting my nails. I have tried every technique possible to break this habit. I have tried the salt on the nails to where you bite them and they have a bad taste. that didn't work, i just picked the salt out. My mom tried buying me the "no bite" polish that makes your tongue go numb and that didn't work. and i try keeping them painted so i don't bite them, but that doesn't work either! so anyone who knows the secret of breaking this habit, please share :)