Fans are already speculating that the song may have been written about One Direction's Harry Styles. But don’t take our word for it: Taylor opened up about her inspiration for the song in a videoposted to her YouTube page on Monday.
"This was a relationship where it was kind of living day to day, wondering where it was going, and if it was gonna go anywhere, if it was going to end the next day," Taylor, 24, said. "It was a relationship where you kind of felt you were never standing on solid ground. And that kind of a feeling brings on excitement, but also extreme anxiety, and kind of a frantic feeling of wondering."
Taylor gave us a hint about the track in her revealing Rolling Stonecover story last month. More specifically, she explained the line, "Remember when you hit the brakes too soon/Twenty stitches in a hospital room."