I knew him pretty well, we had a few inebriated dinners together. (Didn't start off inebriated, but we kicked off with martinis, then moved on to wine with the meal. I remember turning green once during the after-dinner cigars... )
He made a joke at a Dean's meeting, one of the Deans raised hell. He apologized.
He was tired of administration. He left to go back to New York, and back to the classroom.