Uninsured Motorist Coverage - UM
  
It's for when you get hit...by that dude who was texting and never bothered to renew his insurance and just hasn't been nailed by the cops yet. He rammed into your left side. The door won't open. The transmission will never be the same. Luckily, your body will be.
Total bill: $12,000. The problem: the guy who hit you has no insurance. He just gets out of his car, says, "Sorry, dude" and walks away. You could sue him, but he has no assets. He has 8 grand in credit card debt and makes barely enough to pay for food. So...you're financially screwed. Unless you have UMC, which pays the 12 grand for your troubles, and likely makes the rest of the guy-who-hit-you's financial life miserable. That insurance company has armies of lawyers who will go after the hitter for decades.
Yes, there is justice and karma in the world.