The book, of Mice and Men, has different themes. The characters Slim, Crooks and Curley are directly involved in putting emphasis on three of the main themes.
The story recalls the lives of George Milton and Lennie Small who have big dreams. We observe how they manage to overcome their hardships working as migrant labourers on a ranch and how people in those days interacted with one another.
Slim, is highly respected on the ranch. He is the friend who George confides in and the only person who understands George and Lennies friendship. His word is always taken when it comes to advice. In my opinion, Slim is there to be the understanding friend for George when problems occur. He puts emphasis on the theme, friendship.
The theme loneliness is related to the character, Crooks. He is there to show people the problems race caused in those days. We learn about his life being a coloured person and how it changed over the years. He is a crippled man who keeps to himself as he is not accepted among others because of his skin colour. He acts proud but is actually lonely.
Because he is married, Curley has become protective over his wife. He does not like men who are physically bigger than him. In the story, He plays the bad guy who tortures Lennie. Curley puts emphasis on the fact that it is not only today where people do not get along but then too. He enjoys causing trouble which adds to the theme of meanness.
From the above mentioned, one can notice that on the ranch, there were many different people. This story taught us that friendship, respect and just listening to ones opinions and accepting another can conquer almost everything.