The best definition I ever heard for jazz is this: Jazz = the sound of surprise. Naysayers and musicologists may cry, “But that doesn’t define jazz, you have to say more!” Nah, I don’t, cuz the word “surprise” implies that you expected something different than what you heard before, and that is jazz, exactly. That’s right, jazz is all about cover tunes. (yet NOT cover songs, which is key to comprehending this particular rant) But what about all those “original” jazz tunes? Sorry, but there’s no such thing; jazz musicians study, they know all the popular chord progressions by heart already, and there’s nothing new under the sun. Truly, there are only so many things you can do with a given instrument that people will respond to; learn to do ’em, and the folks will drop a buck in your hat. It’s like the difference between a fine artist and a commercial artist; one confounds your expectations, the other confirms them. This is why most jazz artists are poor.