This sound comes from Horrid Henry, the British children's character known from the books and the animated television series. In the clip, Henry realizes he has been left behind and immediately celebrates not having to go along with the others. Online, the line gets reused as a reaction audio for moments when someone unexpectedly avoids chores, trips or awkward social plans. It stays popular because Henry's whiny, mischievous delivery is easy to recognize and the emotional switch from worry to happiness makes the joke clear fast.