I am currently in the middle of re-doing our bathroom. Tomorrow the bath and its waste pipe are due to come out. This morning I was having a shower, only for my wife to shout that water was coming through the ceiling. Normally I'd have stopped showering and investigated, but my current contract is ending and I was due at an interview for another company at 08:00, so had no choice but to finish off.
Got back at lunchtime to find a chunk of the hall ceiling on the floor and chunks of plasterboard falling off every few minutes.
After 18 years in the house, a joint in the middle of the waste pipe that has been there longer than that has slipped off the day before it was due to be ripped out.
I presume it was disturbed by the other work - or maybe it was a pre-emptive strike.
SteveW