Wham!, "Last Christmas" (1985)
It's rare for a modern pop hit to break into the Christmas standard canon, but Wham! – and later, Mariah Carey – did just that with holiday break-up anthem "Last Christmas." The bittersweet tune has become a seasonal classic and one of the biggest-selling singles in the U.K. not to actually reach Number One. Over the years, the song has been covered by a range of artists, including Jimmy Eat World, Hilary Duff, Ariana Grande, Taylor Swift, Avril Lavigne and Carly Rae Jepsen.