So, that was fun. Putting some clothes in the dryer last night, and it fell off the wall, bounced off me (breaking my watch in the process) and landed on the washing machine.
The dryer was mounted on a wooden board which the previous owners of the house had attached directly to the drywall, not to a stud. So it gradually vibrated loose, and then the whole kaboodle fell off.
Glad it was me, not my pregnant wife!