I have a theory that when Michael got jacked in the face by McClusky, and had his jaw broken.....his apperance changed,but so did his way of thinking.....he became cold hearted, and very cunning......and he never went back to the old Michael....looks wise or attitude wise.... I look at that moment and see Michael Corleon dying, and Don Michael Corleon the Godfather being born.
Anyone agree??? Just a theory mind you........