Having been John many times in my career, I've come to wonder, would the organization have made those changes years later despite John or because of him.

I'm usually hoping those places I leave, while I might have been too impatient to get things done, I left a mark on people, whom still remember what I was talking about and what I suggested. There are smart people out there, one probably came in and was effective where I had failed, but given a vision and even one dislike, they can be just like a really bad but catchy song.

I don't know John (at least I don't think I do), but what really helped me improve as a leader is to remember that most people want to be right, and don't want to be enlightened and don't want to learn. The job is to make change happen despite them, not to tell them they are wrong, give up, and run away.