When something is established for the purposes of a gag, but is then forgotten about in future situations where it would apply.
Can also be a Compressed Vice
- In Reno 911!, when Deputy Junior is told to remove his omnipresent Cool Shades during the indictment of the Reno Sheriff's Department, he is revealed to be crosseyed, complete with the Punch Line that he's the best shot in the department. In other scenes where he's not wearing his sunglasses, though (a bust where he was told to take them off and his appearances acting in the PSA bits), his eyes are straight.
- In one Are You Being Served? Mr. Lucas's first name is revealed to be Dick, which everyone else find hilarious. But in every other episode where his first name is mentioned, it's James.