Oh, Taylor Swift! You just can't NOT write songs about exes! "I Knew You Were Trouble" is very publicly about One Direction's Harry Styles.
While she plays coy when asked directly, it's a pretty sure thing that Eric Clapton was Sheryl Crow's "Favorite Mistake."
Eric Clapton wrote "Layla" about Pattie Boyd when the model was still married to George Harrison. She later left Harrison and married Clapton.
311's Amber was inspired by Nick Hexum's relationship with former Pussycat Doll Nicole Scherzinger.
Kate Moss and her troubled and chaotic relationship with Babyshambles member Pete Doherty inspired "What Katie Did Next."
While Taylor Swift used coded language in some of her other breakup songs, she straight up called John Mayer out in "Dear John."
INXS' late Michael Hutchence wrote "Suicide Blonde" about then-girlfriend Kylie Minogue after she died her hair platinum.
The greatest product to come out of Chris Martin and Gwyneth Paltrow's marriage was Coldplay's "Fix You," which Martin wrote for Paltrow when her father died.
When John Nolan slept with Brand New singer's girlfriend, Brand New wrote "Seventy Times Seven" wishing for Nolan's death.
After Trent Reznor helped Marilyn Manson produce Antichrist Superstar, Manson and Reznor had a fight, which led to Nine Inch Nails' "Starf*ckers, Inc."
Taylor Swift's "The Last Time" is allegedly about her relationship with Jake Gyllenhaal and all the ways in which he was so unreliable.
Taking Back Sunday responded to Brand New's song about John Nolan with "There's No I in Team," which they flippantly called an apology.
The Velvet Underground's "Femme Fatale" was written by Lou Reed about Andy Warhol's muse, Edie Sedgwick.
After a few jabs in his direction from Sir Paul McCartney, John Lennon wrote "How Do You Sleep?" as a rebuttal.
John Lennon wrote The Beatles' song "Dear Prudence" for Mia Farrow's sister Prudence in 1967 to help her battle depression.
Julian Casablancas, from the Strokes, is said to have inspired Courtney Love's lust-fest "But Julian, I'm a Little Older Than You."
Courtney Love's hatred of Billy Corgan (Smashing Pumpkins) inspired Hole's "Violet."
"Hollaback Girl" appeared on Gwen Stefani's solo album and is reportedly about a spat with Courtney Love.
It's probably safe to say that "Shake It Off" is about ALL of Taylor Swift's exes, the list of which is nearly too numerous to list here.