Because Kitty is the narrator of GILT, songs for and about her featured heavily on my playlist while I was writing it. Some of the songs were contradictory. Some were descriptive. One or two songs illustrated Kitty as she became - long after the action of the novel passed. (I write with the long view in mind, one of the perks of writing historical fiction!)
Avril Lavigne's COMPLIC8TED didn't make it onto my iPod. I didn't listen to it while I took my long walks to get through plot points. I never heard it at the gym while I was working off writerly excitement or frustration. But I kept coming back to it on YouTube.
Because Kitty needed to hear it.
But then, we learn through life, don't we? Some things can't be learned through lecture. Sometimes, only experience can teach us the hardest lessons.