Oscar's behavior
To quote 'The Works',on Oscars behavior:
"Preschoolers know all about grouches-they can be pretty grumpy themselves.That's why they have no difficulty in identifying with Oscar,the ultimate Grouch.To say that Oscar-who lives in a garbage can-is a skeptic is to indulge in understatement. He takes nothing on trust,and he is not shy about expressing his disdain for the mealy-mouthed politeness practiced by the other inhabitants of Sesame Street. Somehow,though,he manages to remain a sympathetic character."
Oscar does have his mood swings,but he does manage also to lighten up every once in awhile.
Hope that helps a little Brian.