This song is about the breakup of Swift's relationship with Joe Jonas. She told The Los Angeles Times October 26, 2008: "It's about watching somebody fade away in a relationship. They said they were going to be with you forever, that they loved you, and then something changed in the relationship and you don't know what it is, but you're watching them slowly drift. That emotion of rejection, for me, usually starts out sad and then gets mad. This song starts with this pretty melody that's easy to sing along with, then in the end I'm basically screaming it because I'm so mad. I'm really proud of that."
Swift told The Los Angeles Times that on this song, she felt as though she achieved something authentic and raw. She explained: "When I go into the studio, it's really more about portraying the song in a way that gets the feeling across, rather than every phrase being exactly perfect. I think it's the writer in me that's a little more obsessed with the meaning of the song than the vocal technique. All that stuff is like math to me. Over-thinking vocals and stuff - I never want to get to that point."
Swift wrote this near the end of the recording process after she broke up with Joe Jonas. The singer had to plead with the president of her record label, Scott Borchetta, to let her add it to the album a day before the final version was due to be turned in.
Joe Jonas told the June 2009 issue of Seventeen magazine that he wasn't bothered about Taylor writing about the break-up of their relationship. He said: "It's flattering. It's always nice to hear their side of the story."