The hangdog (hangmouse?) expression on Mickey's face when his master comes back and discovers the flooded castle, full of enchanted mops. The moral of the story is that it's best to take pride in your work and do it properly, and also that you should just never clean house because it'll only lead to trouble. Here, he's the over-enthusiastic but under-disciplined assistant to a sorcerer, who tries to take a short-cut when his master is out of town and ends up with hundreds of magical mops flooding his home - and he's wonderful at it. The most famous cartoon of all time, all the way down here? Why yes, because Mickey Mouse has never been a big character in feature-length animation, and his best performance was in a tiny segment of classical music oddity Fantasia.
