Is there music that you just have to stop and concentrate to enjoy?

You can’t have it on as background music because it demands your full attention.

I was listening to the Bagatelles by Bela Bartok last night reading a book and I had to put down the book to listen to them. (I realize that’s a very obscure reference that most people won’t have heard, but it’s on my mind). Another example is Tool Lateralus.