This scene shows Carlson killing Candy's dog and shows that Carlson is not very compassionate because he could not see why Candy was upset. We can see that he is very insensitive and that he does not empathize well.
The theme of loneliness can be connected to Curley's wife. She could not talk to any other guy except Curley and was left out even though she was surrounded by others.
Simile:His huge companion dropped his blankets and flung himself down and drank from the surface of the green pool; drank with long gulps, snorting into the water like a horse (8).