The clip comes from Step Brothers, the 2008 comedy about two grown men who become stepbrothers and spend much of the film refusing to behave like adults. Lines like this one spread through soundboards and short-form video because they sum up the film's central joke in a few seconds: adults insisting on maturity while acting like children. Creators still reuse it as a reaction sound because the premise is instantly recognisable, even for viewers who have not seen the full film, and it fits almost any moment of petty, immature behaviour.