On TV Carson was witty, charming, and personable. He used his time to make his guests shine, to draw them out and then share his witty commentary on their stories.
In real life, apparently he was something of a misanthrope who didn't care for other people much and just wanted to be alone. Weird how he could flip a switch and be that guy on TV that everybody loved and how he couldnt be that guy in real life. A fascinating, flawed man but no doubt the greatest late night host of all time, period.
I have read several things on Carson and he was pretty much the loner when not on TV. Even those few he was close friends with had a time understanding him. He was very close to Michael Landon but when he got sick he could not deal with it and did not even go to the funeral.
There is a story that when he was in the Navy during the end of W.W. II he was on a ship that had a terrible accident. He was the one detailed to take care of the bodies of those that drowned in a forward area and it took days to carry it out. It was said that experience forever changed him, so who knows, he was complicated but was a wonderful entertainer with his own set of demons.