A recurring joke in Pratchett and Gaiman's Good Omens is that all the music tapes in Crowley's car are songs from Queen, which is apparently a British rock band. From near the start of the book:
Crowley was currently doing 110 mph somewhere east of Slough. Nothing about him looked particularly demonic, at least by classical standards. No horns, no wings. Admittedly he was listening to a Best of Queen tape, but no conclusions should be drawn from this because all tapes left in a car for more than about a fortnight metamorphose into Best of Queen albums.
This joke is picked up again and again throughout the book, as Crowley and Aziraphale try to play various tapes in his car - Tchaikovsky, Vivaldi, etc. - and always get a Queen-ified version. Possibly due to my utter ignorance about popular music, I don't get the joke.
Why do tapes left in a car turn into Queen albums, specifically?