The telling lyrics: "I say I heard that you been out and about with some other girl / Some other girl / He says, what you've heard it's true but I / Can't stop thinking about you . . . You got that long hair, slicked back, white t-shirt"
Who it's supposed to be about: Harry Styles
Why? The two had a blink-and-you-missed-it romance, and the lead in the video is a dead ringer for Styles. Also, the song is called "Style," so . . .