Widescreen Cropping

The Simpsons
The episodes are widescreen cropped on most modern TV airings.

SpongeBob SquarePants
When the "Golden Age Set" (seasons 1-3) were released on Blu-ray, the show was cropped into widescreen, with some exceptions, like the TV scenes, the title cards (which were stretched out) and SB-129's opening credits (also strechecd out).