Fingernails, a top can pull out the ears, the bottom can scratch, and occasionally squeeze a pimple body parts, daily commitment to use the most thin body to complete the most things. But there are always people whose nails are not up to the task, not for nothing, but their nails are forced to be very short all year round. The secret to keeping your nails short is “I pick, I chew, I bite, I pick again, I chew again, I bite”. Iron teeth, running nails, in the battle with the teeth day after day, the nail defeat, the gray fall into the trash, compared to many toenails, those defeated under the teeth of the nail, even too late to recognize what is called nail clippers. Pick your nails, bite your nails, these seemingly harmless little habits, really no problem? What magic do they have, in the end, can make people down to a few years old, up to dozens of years old can not help but do it?