Curley is an interesting character in the play. He intrudes. No one likes him, not even his wife. In light of this basic fact, here are a few observations.
First, Curley comes off strong. He demands things from people and he is loud. He has the outer trappings of power and he wants to flaunt it. The reason why he has power is because he is the son of the owner of the ranch. However, this is not to say that the people respect him; they don't. They seem him as a nuisance and a joke.
Second, Curley is also confrontational. He always has something to prove. He yells at people and whenever there is a big guy, he wants to pick a fight, in order to make a point, to show his strength. Of course, he messes with the wrong man when he attacks Lennie.
Finally, Curley is alone. In this sense, we can say that he really does not interact with anyone. This might be the most profound point.