4. Her? - Arrested Development
Arrested Development may actually hold the record for most running gags in a single series. There are a few in practically every episode and a whole bunch that span the entire show, but the greatest one can be summed up with one question: "Her?"
Absolutely no one in the Bluth family can understand what George Michael sees in his girlfriend, Ann, especially not Michael, who continues to forget she exists. Even though she and George Michael date for a lot of the series, he's always seen as not having really settled with her, because after all, why would anyone want to be with Ann?
Like with Toby on The Office, Ann doesn't really do anything wrong to get so much hate; she's just seen as bland and forgettable. In fact, Michael actually calls her Bland at one point on one of the many occasions when he forgets her name. She has also been referred to as Egg, Plant, Plain, Ann Hog, Yam, And, Mouth, and Blank. Gob gets in on it too, asking Michael if she's funny or something. Whenever she's brought up at all, the response tends to be the same question: "Her?"
Originally, it was intended that Ann would be played by a different actress every episode, hammering home just how forgettable she really is. As great as Mae Whitman is, that would have been incredible.