I don't mean to break up the current party; although I don't agree with most of what's been said in regard to various genres and jazz, I'm just one person with one opinion.
Making good jazz music is never easy; the practitioner must spend years mastering his instrument, the same as a concert pianist; but the biggest difference is that jazz comes from within, maybe that's why the concert pianist can never make good jazz.
The concert pianist has all this written music (external), while the jazz pianist has it all internal, and he has worked hard for years to be able to express what he feels.
An example of this is "Bobby Timmons"; no one can express so much with so few notes. While I have noted many references to outstanding musicians, and I can't disagree with that, the complexity of the music might indicate the mastery of the instrument, but we're talking about "jazz"; somehow this music has to reach people on a deeper level, it has to "resonate" some profound innermost feelings; those are the feeling the jazz musician has sought to express in a meaningful way for his entire life. When he is successful, there is resonance, and we are in harmony with his music.
Music is a very personal thing for each individual; for me, I no longer listen with an attempt to evaluate the music, I simply turn the music on, and if it finds me, (achieves resonance and harmony) the music is a keeper, if not, on to the next thing.