Psmith/Funny

• Any time Psmith does his "the cry goes round the castle walls..."-type Mad Libs Catchphrase, especially since he usually saves it for moments when his Sesquipedalian Loquaciousness is entirely inappropriate.
• Mike's first day at the bank in Psmith in the City:

'I've come,' was the best speech he could think of. It was not a good speech. It was too sinister. He felt that even as he said it. It was the sort of thing Mephistopheles would have said to Faust by way of opening conversation.

• Psmith starts out his friendship with Mike by helping him steal a study. In order to actually explain why this is funny, I'd have to copy-paste the entire scene.