Sheldon turning down Amy's advances, and telling her to try again once she grows the hell up.
Everyone tries to guilt Charlotte into identifying her rapist, but she refuses. When Cooper finds out, he doesn't ask her to identify the rapist - he just says he's going to buy a gun and make it look like a mugging, but there is no way the rapist is going to get away with it. This in turn gave Charlotte the strength to identify her attacker.
