I was particularly interested to note Twain's change in attitude as his years increased. Most especially visible in The Mysterious Stranger, he seems to have become quite bitter that humanity didn't turn out nearly as good as he had hoped.
I was also so amused by the recent carnival of crime story, wherein a man kills his conscience, that I re-read it after finishing the book. Quite amusing. As the stories continued toward the end of the book, I found myself agreeing more and more with Twain's interpretation of the basic scoundrel qualities of humanity, but rather than being embittered by it, as Twain seems to have become, I've found that it makes man much more understandable. It seems easier to think of man as a fiendish thing, with exceptions occasionally rearing their heads, rather than as a noble creature, with the occasional fiend.
With the former, those qualities that Twain might call more angelic show themselves more readily. We as a race spend far too much time thinking we're superior. Or so it seems. If we accept our heritage as creatures capable of tremendous evil, then our steps into a better, more ideal temperance will be things to cherish.