George and Lennie as always, are discussing over unimportant topics, because of Lennie's special conditions and George's lack of patience. George is mad at Lennie for various reasons, but mostly because Lennie always get them fired from their jobs because of his mental disability.
The society believes that George and Lennie are nothing just because they are ranchers. They are lonely and don't get quality jobs, they are also mistreated and in the case of Lennie discriminated by his disabilities.
People are harshly treated for their skin color; black people were living in poor conditions and treated like slaves when they haven't done anything wrong. That is the case of the guy showing Lennie and George around, who explained how his boss treated differently black people.