I once had a manager who was extremely quiet and very good at winning arguments. They too would never argue. Instead they would present themselves in as supportive of a way as possible, and then just ask questions. There was never a point in the questioning where he would declare you made a mistake. Instead, he would just remain silent and maybe write something down. It was astonishing to watch. There was no counter to it. Maybe the clock, but he was persistent too, like Colombo.