I found the following from The Pine Bluff Commercial and I think it partially explains why people thought so much of him. You can read the rest of their thoughts in the above link.
For he not only knew other people, and understood something about their infinite variety, but at those moments he seemed to be appraising himself, too. Accurately enough, maybe, but entirely too harshly. As when, after one of those silly campaign smears about his not having religion, or at least not the right kind, he talked about it in an interview "I'm trying to read the Bible every day for Lent," he said, "but I'm a pretty big-time sinner." (Did we mention that he was prone to exaggerate? But in a way that won your heart.) "I cuss. I'm prideful. I'm arrogant," he went on. "I can name 50 sins I commit every day. I wish sometimes I could be more humble. I really do." Who wouldn't love a sinner like that? When we lost him Wednesday, he'd already made full confession in that interview. After that, he was always in a state of grace with us.