The boss pointed a playful finger at Lennie. "He ain't much of a talker, is he?"
"No, he ain't, but he's sure a hell of a good worker. Strong as a bull."
Lennie smiled to himself. "Strong as a bull," he repeated.
George scowled at him, and Lennie dropped his head in shame at having forgotten. (2.35-38)
Lennie is all brawn, and no brains—which, in Of Mice and Men, is a pretty dangerous combination. Of course, the opposite is true, too. You can't say that Curley is all brains, but he's definitely smarter than a lot of the ranchhands—smarter and smaller. Either way, you're out of luck. (Unless you're Slim.)