re: The impression I got
That was my general impression, too. I never met Shepard, but comparing him to the other Right Stuff types and the newer Shuttle astronauts, the latter seemed more willing to mingle with us peasants who did not obtain Mount Olympus, whereas many of the early astronauts, if they were the Sun, we would have all frozen to death long ago.
I know, I know, they aren't all like that and they had to be tough as nails, etc., etc., and let's face it, NASA's top priority was never psychology and socialization. Makes me think the "old" guys would have gone bonkers on a Mars mission.