The most evident physical danger comes from walking around all day. It puts a lot of wear and tear on your body. You'll also be walking around wet and greasy areas, so slips and falls are quite common. Arm and shoulder strains are also common from carrying heavy loads of food and dishes. Occasionally you may get burned, either from hot plates or by bumping up against a hot appliance in the kitchen of the restaurant. And finger cracking (not knuckle cracking) is quite common. From all of the hand washing that is required, the ends of your fingers can become quite cracked. Hope you aren't pursuing a hand modeling career on the side.