The exact source of this "I'm bussing" clip is unclear from the available information, but the phrase itself comes from internet slang where "bussin" means very good, especially about food. The audio fits the style of short-form meme reactions that spread through reposts, edits and soundboard clips. It stays popular because the wording is instantly recognizable, easy to drop into food content, and funny when used as an exaggerated stamp of approval on something clearly overdone.