" Great means unsettling. Great means open to criticism. Great means booed off stage.
And great music, like a great idea, spreads. Ideas that spread, win, and so the goal today is not to make great music for 1970 or 1990, but great music for today, for a market that's super picky and selfish and has ADD.
Great is in the ear of the listener, of course, and the definition is simple: if it spreads, then for this market, it's great."