Control your emotions (1950)

Jeff Moore, a high school student, has trouble controlling his emotions. An expert in the subject (though it's never explained who he is or what he's an expert in) assures the audience that Jeff's problems stem from the fact that he lets his emotions escape, instead of reining them in like everyone is supposed to. At the end, Jeff realizes that he must not let his emotions get in the way of logic and reason, and goes to a marshmallow roast with the gang.