I love the blues. I love to jam and play by ear and improvise in lots of styles. In fact I'm discovering I like it more than through-composed music. So I'm in a bit of an existential pickle these days. :)
I had to basically quit playing classical music (I was never that good anyway) before I could really get an ear for improvisation. I kept thinking that you had to hit the notes just as the composer intended and I think I sacrificed a lot of the soul of the music in search of perfection.
I think Gerswhin changed the way a lot of people thought about what is or is not classical music. Porgy and Bess was a paradigm shift for opera.
I think Mozart would have been a great jazz pianist. I'm just suprised he didn't invent it.