Both Crooks and Curley's wife have been marginalized as they possess single identities that differ from all the other people on the ranch.
Within the setting of the 1930's, Crooks finds himself subjected to the racial bias of this era. Even though he is probably better educated than many of the other ranch hands, he is made to live in the barn with the mules and horses, and is subjected to verbal abuse and being called pejorative racial names. In Chapter 2, for instance, the old swamper named Candy tells George and Lennie that the boss has been angered by their late arrival and has yelled at the stable buck:
"He sure was burned....Come right in when we was eatin' breakfast and says, 'Where the hell's them new men?' An' he give the stable buck hell, too."
"Give the stable buck hell?" [George] asked.
"Sure. Ya see the stable buck's a nigger."
Yeah....The boss gives him hell when he's mad."
In Chapter 4, Lennie enters the barn while the other men and George have gone to town. There he wanders around and finds Crooks in the harness room. Crooks lives in this barn because he is not allowed in the bunkhouse and has a bed made from a long box filled with straw. Seeing Lennie, Crooks tries to prevent him from entering, but the child-like man does not understand why Crooks is unfriendly. Crooks provides Lennie the reason by saying that Lennie should not enter his room since he is not wanted in the bunkhouse. When Lennie asks why Crooks is kept out, Crooks tells him,
"'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."
Further, Crooks complains of his alienation: "If I say something, why it's just a nigger sayin' it."
As he talks with Lennie, Crooks also reveals his loneliness:
"A guy needs somebody--to be near him....A guy goes nuts if he ain't got nobody....I tell ya a guy gets too lonely an' he gets sick...."
"Maybe if he sees somethin', he don't know whether it's right or not. He can't turn to some other guy and ast him if he sees it, too. He can't tell. He got nothing to measure by."
Later, when Crooks tries to get Curley's wife to leave after she appears in the barn, he tells her she has no right to come into his room. And, he adds that he will tell the boss to not let her come into the barn. These remarks anger Curley's wife and she retorts venomously,
"Listen, Nigger....You know what I can do to you if you open your trap?....I could get you strung up on a tree so easy it ain't even funny."
Knowing that this could happen to him, Crooks, must become submissive. So, he replies, "Yes, ma'am."
In Chapter 5, Curley's wife enters the barn and finds Lennie in a stall covering his dead puppy. When she kneels in the hay next to him, Lennie objects, "George says I ain't to have nothing to do with you--talk to you or nothing." Curley's wife tells Lennie that the men are all at a horseshoe tournament, suggesting that no one will know if he talks to her.
"Why can't I talk to you? I never get to talk to nobody. I get awful lonely....You can talk to people, but I can't talk to nobody but Curley. Else he gets mad. How'd you like not to talk to anybody?"
When Lennie insists that he cannot talk to her, Curley's wife becomes angry.
"Wha's the matter with me?....Ain't I got a right to talk to nobody? Whatta they think I am, anyways?....I tell you, I ain't used to livin' like this."
She goes on to tell Lennie that she lived in Salinas, implying that she was around people before marrying Curley and suffers now from loneliness.
Clearly, the alienation of Crooks and Curley's wife both has caused them to become resentful of others and greatly dissatisfied in their lives.