Quit smoking by replacing tobacco with carrots every time you crave. For one very good reason: people who eat a lot of produce smoke less during the day, and thus have a softer time to quit. If you often bite your nails, try chewing gum instead. If you tend to break your knuckles, try to find another job with your hands, like grabbing a soft ball or practicing doodles. Use your creativity to find alternatives! You never know if anything will work until you try it.