A cemetery doesn't seem like the best place for a joke, but these dead folks beg to differ! Many of these individuals wanted their loved ones to be able to look down on their tombstone in remembrance in a happy light instead of a sad one. It's better to leave them laughing than crying.
This person left their loved ones with a grim reminder... We're all going to end up where they are at some point! They must have had a pretty dark sense of humor.