“Guy don’t need no sense to be a nice fella. Seems to me sometimes it jus’ works the other way around. Take a real smart guy and he ain’t hardly ever a nice fella.”
– John Steinbeck
Of Mice and Men, Chapter 3. The wise, insightful and non-judgemental Slim is talking here about Lennie. He is such a “nice fella” he doesn’t see he is being targeted by Curley, whom Slim sees as filled with meanness.