People, let me tell you about the rotator cuff. These little muscles are what anchor your humerus to your scapula, your arm to your shoulder, in what we folks like to call the glenohumeral joint. These little fellows are delicate, essential, and easily damaged. When you see people wincing and pressing their fingers into their shoulder joints, that's what they've hurt. Mess up badly enough, and you can tear your rotator cuff, and then you're out of the game. That's bad news, people, and yet people still insist on messing their shoulders up, right and left, with these awful exercises. Why oh why? Here are the worst shoulder exercises I've seen during all my years walking this green Earth. Don't do them people, stay away.