The exact origin of this specific “good girl” clip is unclear from the available information, but it is commonly circulated as a short reaction audio in anime-focused soundboards and edit communities. Its spread comes from how easy it is to drop into very short videos: one line, one clear emotion, and an immediate payoff. Creators keep using it because the phrase can read as affectionate, sarcastic or dominant depending on the scene, which gives the same audio a lot of meme flexibility.