The sound thing to do if you damage someone's car is to leave a note and explain what happened along with your contact details. People who don't do it are the worst.
A guy returned to his car at the weekend and found a note not from the person that did damage to his car, but someone who tried to stop someone taking a leak against it.
The do-gooder's attempt backfired and they were forced to leg it before return to leave the piece of paper under the wiper blade.
The image was posted on Imgur by lovepeaceandgraffiti.