Diegetic and non-diegetic

I reflect while I sit at my desk in the reference section of the library. Today I was thinking about what makes classic rock such a satisfying meal and "indie" rock such a sad, undernourishing snack. The answer, I think, and I'm sure you'll agree, at least partially, if you give it some thought, and possess my command of vocabulary, is that classic rock is, at its best, non-diegetic. The term, stolen from the world of film, refers to music that finds its way into a movie without being part of the main narrative. For example, when music plays over opening or closing credits (which I always stay around to see because, afterall, it's part of the movie), that's non-diegetic music. But, on the other hand, when Wayne and Garth are driving around listening to Bohemian Rhapsody in Wayne's World, that's diegetic music, because it advances the narrative of the movie, in so far as there is one. In any event, I love the fact that classic rock takes us out of the boring, repetitive monotony of our daily lives, away from the house we share with mom, and the sameness of the peanut-butter sandwich lunch we eat every day in the lunchroom and allows us to visit Xanadu or the Misty Mountains. That is an enormous service! Indie rock, though, tends to be all about the mind-numbing, dreary realities of daily life. Here is an actual lyric from a band called Superchunk: I was a graduate student/but I couldn't finish my thesis/now I'm in a band and I run a record label/you'd think this kind of thing might please us/but it doesn't.