“Problem” is the song that made me fall for Ariana Grande. She’s released more mature music since, but here she gleefully resurrects the gaudiest pop moves of the 90s and 00s, a would-be trainwreck that instead becomes a playground for Ari’s acrobatics. You can tell she’s not just an artist, but a fan. Some of these songs creep up to the line of bad taste (or cross it into outright camp), but the willingness of Bruno Mars to shamelessly crib from the greats, or Miley to name check Jay Z and Britney, makes them go down easier. They love pop, and that love is contagious.