Microwaves
One Christmas my mother in-law microwaved the custard for 20 minutes instead of 2 minutes. The smell of melting plastic wafting from the kitchen gave it away. We took the microwave outside, but the smell persisted, so we had pudding with the windows wide open, wearing thick coats and woolley hats.
The silver lining was she got new microwave which was very simple to operate, instead of a complex one that did everything.