It's a little early for Halloween costumes, but here's a great photo from the Disneyland staff cafeteria in 1961. We're guessing the shot is staged, since Goofy and the astronaut would have a hard time eating with their headgear on, but there's a chance that the smiles are genuine, or at least highly trained. A Disney employee manual from 1962, a year after this photo was taken, has an entire section on how to perform an "Honest Smile":
But, in case you can't develop a genuine interest in people, Disney helpfully provided "a few tricks":
And most importantly:
Nothing like a paycheck to brighten your mood!
[Retronaut via BoingBoing]