My mum has two cats, one is huge and fat, the other is a ball of delicate fluff. The little one likes to sleep in a cardboard box under the boiler, and when the fat one tries to get in and see what all the fuss is about it's just hilarious. He literally spills over the edges.
Really? Cultural thing perhaps. It sits on the wall in my parents utility room and controls the hot water. It gets toasty underneath it where the pipes run into the wall, hence the cat likes to sleep there.