Loneliness is an important theme in Of Mice and Men. However, Crooks is more severely affected than most of the characters. Cut off by color segregation from the gregarious atmosphere of the ranch house, he lives alone in the harness room. He is "more permanent than the other men," and his loneliness is exacerbated by constantly seeing ranch hands come and go. This is one reason why he is so cynical about George and Lennie's dream of buying their own land, as he has seen many former hands fail to accomplish this. Nonetheless, his loneliness is such that, even though he does not believe they will achieve their dream, he offers to come and work for them free of charge if they ever do.
Crooks hesitates to make this suggestion, and it is clearly difficult for him to unbend in this way. It is clear from Steinbeck's description of Crooks that his loneliness is perpetuated by a vicious circle. He is described as "a proud, aloof man" who "kept his distance and demanded that other people keep theirs." When he discovers George and Lennie in his room, he peremptorily orders them to get out, saying:
"I ain't wanted in the bunkhouse, and you ain't wanted in my room."
"Why ain't you wanted?" Lennie asked.
"'Cause I'm black. They play cards in there, but I can't play because I'm black. They say I stink. Well, I tell you, you all of you stink to me."
Years of segregation and harsh treatment have exacerbated Crooks's bitterness and, consequently, his loneliness. He is now hostile to the men who sleep in the bunkhouse, even on the rare occasions when they want to be friends with him. He is envious of George and Lennie's friendship, as well as the camaraderie of the bunkhouse, complaining to Lennie:
You got George. You know he's goin' to come back. S'pose you didn't have nobody. S'pose you couldn't go into the bunkhouse and play rummy 'cause you was black. How'd you like that?...A guy goes nuts if he ain't got nobody.