Stealing, of course, is a crime, and a very impolite thing to do. But like most impolite things, it is excusable under certain circumstances. Stealing is not excusable if, for instance, you are in a museum and you decide that a certain painting would look better in your house, and you simply grab the painting and take it there. But if you were very, very hungry, and you had no way of obtaining money, it would be excusable to grab the painting, take it to your house, and eat it.