Farnsworth's Girlfriend

She turns up on Professor Farnsworth's arm as a surprise to everyone who assumed the ancient, addled inventor had no romantic life at all. Whatever scene she's in, she treats him with an affection that feels genuine and slightly bewildering next to his usual mad-scientist obliviousness, and she rolls with the show's chaos without missing a beat.

The joke is entirely in the premise — that someone finds Farnsworth charming rather than exasperating — and Tress MacNeille, doing what she does best across Futurama's sprawling voice cast, gives her just enough warmth to sell it. It's a small, efficient bit of world-building: the universe contains someone who loves this terrible old man, and that's funny.