When Lennie initially enters the barn, Crooks's conditioned defenses are raised. He resents the invasion of his privacy and the intrusion of a white man into his area when he is not allowed to enter the bunkhouse because he is black. He thinks that Lennie wants to antagonize him or berate him, but when Lennie tells him that he has come into the barn to pet his puppy because George and the others have gone into town, Crooks is somewhat disarmed by both Lennie's smile and and words. Crooks realizes that Lennie is simple and ingenuous. As he talks with Lennie, Crooks starts by teasing Lennie cruelly, saying that George may not return, but Lennie becomes angry, so he stops.
With time, Crooks opens up to Lennie, saying that he is not from the South and, therefore, not used to being treated so badly. He confides some of his feelings with Lennie, especially how lonely he is without someone "to measure" himself by; he, like Lennie and the others, is dispossessed and alienated.