Nothing pisses off Kelly Olynyk more than a poorly run fantasy basketball league -- which is why the Boston Celtics player tore our TMZ photog a new one right in the middle of the street.
Long story short ... our guy is in a league that starts the fantasy playoffs THIS WEEK. Olynyk feels that's wayyyyy too early. He's right.
When our guy tried to explain why (in case NBA playoff-bound teams sit their stars at the end of the regular season) ... Kelly called B.S. and called for the commish to be FIRED.
Kelly's right. Get rid of the guy.