Crooks is a black man, but at the time the novel was written, blacks were referred to as "niggers", meant as a white insult. Being a nigger, Crooks is ostracised by the whites at the ranch and he resents this. As he says (p. 74) "If I say something, why it's just a nigger sayin' it" and this shows his anger at being pushed to the side. Being oppressed has made him seem cruel and gruff, but also has turned him to self-pity and the notion that he is a lesser human. He says to Lennie (p. 72) "You got no right to come in my room.....You go on get outa my room. I ain't wanted in the bunkhouse and you ain't wanted in my room." He continues by saying that the whites believe he stinks and one can interpret this as a way of saying that the whites would find it a disgrace that a nigger should breathe the same bunkhouse air as them. "S'pose you couldn't go into the bunkhouse and play rummy 'cause you was black...Sure, you could play horseshoes 'til dark, but then you have to read books." shows that Crooks pities his own circumstances and vulnerability. However (p. 73) "his tone was a little more friendly" and (p. 77) "I didn't mean to scare you" gives us the impression that Crooks has a kind heart under his blunt exterior.
Crooks brings into perspective the loneliness experienced by all the characters in "Of Mice and Men" by saying (p. 77) "Sure, you could play horseshoes till it got dark, but then you got to read books. Books ain't no good. A guy needs someone - to be near