I interacted with him, sort of, on two occasions. Years ago when he was a congressman, I was leaving a girlfriend's apartment in a slum building in Greenwich Village, and we passed on the stairs as I was going down and he was going up. He had heard complaints about living conditions in the building and was checking them out. I was impressed that a congressman would take time to do that - on a Sunday morning, no less.
Later, when he was mayor, I was walking along West Fourth Street and he was walking in the opposite direction on the other side of the street. He gave me his famous "How am I doing?" shout, and I responded with a thumbs up.
RIP, Mr. Mayor.