The sound comes from the world of Peanuts, where Charlie Brown is the perpetually unlucky boy at the centre of Charles Schulz's comic strip and animated specials. The gentle jazz piano that follows his setbacks became a shorthand for disappointment long before short-form video, and creators later lifted the same feeling for reaction clips and fail compilations. It survives because the melody needs no dialogue or context: a few drooping notes instantly tell viewers that something did not go as planned.