Twain's pessimistic view of human nature

Twain is usually viewed as a harmless humorist who gently mocked the culture that was familiar to him, but he was really a pessimist about human nature. I think that the Grangerford-Shepherdson feud chapters really show this. The feud is so pointless and irrational, and no one even remembers what the trouble was about in the first place, yet they keep on shooting at each other. And how about that scene where they all go to church (with their guns) and listen to a sermon on brotherly love? They're such hypocrites. No wonder Huck is so happy to get back to the raft.