High Fidelity is British novelist Nick Hornby's best known book, and became the 2000 film of the same name. It concerns a mid-30s man named Rob who undergoes a personal and emotional crisis when his girlfriend, Laura, leaves him.
Since Rob is an ex-DJ and owns a record store, music plays an enormous role in his life, from his obsession with creating "top 10" lists (a holdover from radio stations, which often count down song lists) to musing on the purpose of music as a cathartic tool:
What came first -- the music or the misery? Did I listen to music because I was miserable? Or was I miserable because I listened to music? Do all those records turn you into a melancholy person?
Nobody worries about kids listening to thousands -- literally thousands -- of songs about broken hearts and rejection and pain and misery and loss.
(Hornby, High Fidelity, Google Books)
Because of his failed (or at least abandoned) career as a DJ, Rob believes that his life is average and therefore unworthy of the women he meets; music is the only thing in his life that is constant, and so instead of confrontation he retreats into his music, hoping that the world will change around him while he waits. Rob's initial failure to understand why Laura left is based entirely on his misunderstanding of "breakup songs," which almost always portray the leaving partner as in the wrong. As he matures over the course of the novel, he begins to understand music as a reflection of life, not a motivator to it, and he is able to rediscover his own joy in working with music instead of simply selling it.