Concussions. Especially when they are used as plot vehicles where someone is knocked out, and they wake up in a jail cell or whatever.

If you got hit THAT hard on the head that you’re unconscious and unresponsive for hours? You are going to wake up dizzy, nauseated, and disoriented with a huge headache, loss of motor control, and a disorienting tinnitus. Possibly permanently. Your brain swelled up and cut off blood flow. You might look like a stroke victim. You will not wake up, rub your head, then pick a lock in a dark room and construct a bomb with a gum wrapper and a smoke detector battery. You will weep, vomit, and be unable to walk straight until you get real medical attention.

Some action stars get knocked out almost every episode. I think MacGyver would have been mentally incapacitated after just a few shows.