John collaborated with Taylor Swift on the song "Half of My Heart" for his Battle Studies album, and a romance blossomed. After it fizzled, Taylor Swift put pen to paper; not only did she title her 2010 song "Dear John," but the tune also included lyrics like, "You are an expert at sorry and keeping lines blurry, never impressed by me acing your tests" and "Don't you think 19's too young to be played by your dark twisted games?" John caught wind of the takedown and admitted to being "really humiliated," adding, "I'm pretty good at taking accountability now, and I never did anything to deserve that. It was a really lousy thing for her to do."
Three years after the release of "Dear John," John Mayer put out a rebuttal called "Paper Doll." The lyrics, "You're like 22 girls in one, and none of them know what they're running from. Was it just too far to fall for a little paper doll?" are likely in reference to Taylor's hit "22," which had come out in 2012.