I've always known that you cannot stall (regular turn off by turning key (i'm not sure how that's called in english)) an engine if it is not yet reached it's work temperature. For example, if i go to a store and it's close enough for the car to not be able to warm up, i would take a slightly longer route so that the engine can warm up to working temperature. That's kind of been ingrained in me by my father. But i do not know why.
So the question is --
what damage (if any) is caused by not allowing the car to warm up before stalling it?