The fa la la refrain comes from Deck the Halls, a traditional Christmas carol whose joyful nonsense syllables have made it instantly recognisable for generations. Unlike carols built around a story, its appeal lies in the singalong chorus itself, which is why short excerpts work so well outside a full performance. Online, creators have reused brief festive vocal clips like this one to mark the start of the holiday season, add warmth to December videos and signal Christmas without needing a whole song. Its familiarity keeps it useful year after year.