The Apartment (1960)

Factual error: Jack Lemmon cooks spaghetti for Xmas dinner. On New Years Eve he picks up the tennis racket, through which he had poured the spaghetti, and one piece hangs limp from the racket. It would of course, have long dried and be hard as before cooking.

C.C. Baxter: The mirror... It's broken.
Fran Kubelik: Yes, I know. I like it that way. Makes me look the way I feel.

Trivia: To make the office appear larger than it was, the team used forced perspective - adult actors at the front, with child actors behind them, and tiny desks with wire-operated dolls at the back.