I ruined one of my car keys trying to open my trunk, it was so full of stuff that some of the junk inside was up against the lock mechanism inside. I finally forced it open, but I damaged the key so much in the process that it will no longer work. Good thing I have a spare I keep in my wallet (in case I ever lock my keys inside, which I have on occasion).
My dad recently related the story of his car door not opening one morning (he lives in a colder climate), it seems the temperature had dropped low enough to freeze the car doors so they wouldn't open.
This little post may not seem to have much point, but then, maybe that is my point.