making love to the sound of keytars

Ok so I've been wondering about this thing for a while now. I see old people with headphones every time I walk outside. They're friggin everywhere and they always wear those really old crappy 'phones similar to the ones you get on airplanes. These are most of the time plugged into an ipod.
Every time I see one of them I wonder, "what's that person listening to?" Are they all listening to old time classics, mainstream pop or hardcore german techno? And why do they keep insisting on using those crappy headphones?
They walk there, looking really concentrated and they're obviously listening to something they appreciate but I can never hear what it is... It's so annoying!

DFKU