The other day I was listening to a bit of hard core, or possibly thrash metal, the way you do. At least, the way you do if your children insist on listening to Radio 1 sometime around midnight when you pick them up, even if they can't stand the music. And I had a bit of an epiphany.
For a long time I have struggled to articulate why I dislike rap so much - and hearing this stuff made me realize what the answer is. I didn't enjoy the hardcore/thrash sounds that were coming from the car speakers. It really wasn't my kind of thing. The closest you'll find on my iPod is somewhere between Van der Graaf Generator and Pink Floyd at their most destructive. But I could appreciate what I was hearing as music. It clearly was someone producing music, and what they were doing had obvious antecedents in the musical tradition.
What I hear when I listen to a rap 'song' has a totally different antecedent. Where those extreme forms of rock grew from heavy metal, which came out of mainstream rock, rap clearly came out of a child, standing on a kitchen table showing off. Saying 'Hey, this is me! Aren't I clever with all these words I can say? Look at me! This is my name. Aren't I great?'
The reason I've never understood rap is that I was thinking of it as music, rather than simply childish showing off. Silly me. Now I get it.