I woke up about 4:45 am, with a need to...well answer the call of nature.
When I put my feet on the floor, they were...wet. Suddenly, I was wide awake.
My bedroom was flooded.
My brand-new toilet, in the adjacent bathroom, had been running, and ran enough to, well, flood.
The toilet runs from time to time because... When it was delivered, the styrofoam shipping packing in the water tank had crumbled, and there are still tiny styrofoam beads in the tank, despite many cleaning cycles.
Mopping. For an hour.
Looking on the bright side, my bedroom floor (thankfully hardwood and not carpet) is very, very clean.