Diving in shallow water or diving into a rocky bottom is extremely dangerous. Unfortunately, alcohol plays a role in many recreational accidents. Drinking and driving a boat doesn't make any more sense than driving while intoxicated. In any sport that involves a ball, puck or stick flying through the air, brain injury is a risk. Golfers, too, can find themselves in the path of an errant shot.
Awareness is a key factor in prevention.
Make safety a primary consideration in the work place. When possible, take a short break when you are getting tired. Fatigue, combined with machinery, can result in an accident. Regardless of how careful you are, accidents do happen. Any head injury which is severe enough to cause bleeding or a bruise could also fracture the skull or cause concussion.