My mother-in-law-to-be nearly blew up my entire block of flats with her cooking.
She was staying at our flat with her sister while the missus took the cousin out for the day. I'd wisely run home for the weekend.
We have a gas hob and she has only every used electric hobs.
Because the MIL and her sister smoke like chimneys, they both have absolutely no sense of smell. Also, because they live in the deepest darkest depths of the countryside they're also a bit unfamiliar with cities anyway and so any unusual industrial smell could therefore, in their minds, be what a city is supposed to smell like.
It was later that afternoon that there was a knock on the door. An extremely worried gas engineer was standing in the hallway and apparently opened up with "Hi, we've had a report there's a gas leak but I've been unable to find it and...."
The next part of the sentence rhymes with 'clucking bell'.
It turns out my MIL had nudged one of the dials on the hob while cleaning it and for the entire afternoon the hob had been quietly pumping out gas throughout the whole flat. As smoking is forbidden in our flat, thankfully they'd been going outside to smoke but any of the electrics could have sparked and ignited a flat filled with gas, which I daresay might have made a bit of a dent in the building.
My mother-in-law is now banned from our kitchen indefinitely.
I am aware how much this story sounds like a Simpsons episode; sadly, I'm really not making this up.