Hey Arnold was a Nickelodeon animated series that ran from 1996 to 2004, following Arnold and his friends in the fictional city of Hillwood. Short, quotable lines from 1990s cartoons like this one have stayed popular because they are instantly recognisable to viewers who grew up with the show, while still working for younger audiences who know the characters from clips and reruns. On soundboards and in short-form videos, the line is now used less as a direct quote and more as a shorthand reaction to someone overlooking something obvious.