Johnny Learns His Manners (1946)

In this late Hugh Harman cartoon, little Johnny is slovenly, ill-mannered, argumentative, and gradually turns into a pig so that he shouldn't have listen to his Good Self and somehow learned from his Bad Self.

A modern fable in animated form, this is the story of a 'piggish' little boy who learned the hard way that good maners, cooperation and consideration really do benefit oneself. This film is a humorous visualization of basic concepts: good manners and consideration for others result in acceptance, while bad manners are liked by none. Youngsters will enjoy learning this valuable lesson.

Note: am I the only one thinking this short is set during the Summer Vacation or a Saturday!