The things that make me angry still make me angry. George Carlin is 67, and he's still as funny as he's ever been, and he's still angry. And that makes me feel good, because I feel like if I stick around long enough, I'll still be able to work.
In a way, the history of jazz's development is a small mirror of classical music's development through the centuries. Now jazz is a living form of original music, while classical music has gotten to the end of its cycle in terms of exploring its form.