This is probably in the holy trinity of Selena Gomez singles ("Love You Like a Song" and "Come & Get It" are in there, too). The instrumental is probably the greatest part of this song, the synths are incredibly addictive. And who doesn't love a little Charli XCX?
This song is just super cool to me. I LOVE how it's like listening to a scene from a musical or theatrical performance. It gives this track such great life and meaning.