Your hand shakes while you're holding a coffee cup, signing a form or trying to thread a needle. The question that follows is simple: why, and should you worry? For most people, an occasional shake is nothing serious. Too much caffeine, a bad night's sleep or nerves before a big meeting can all be the cause. For others, it's an early sign of a neurological condition, and finding out early makes a real difference. This guide covers what causes shaking hands, from common everyd