The original question had to be edited down. Steinbeck's depiction of the relationship between workers and supervisors is as distinctive as the characterizations he illuminates in the novel. On one hand, there are the traditional "supervisors" or those in the position of power over others. Curley demonstrates power to the extent that he is the boss' son and demands instant respect from everyone he encounters. When his wife's body is discovered, he represents the force of power in the manner he hunts down Lennie. He leads the lynch mob and others, like Carlson, blindly follow. In contrast to this, Slim is a supervisor who commands respect by not demanding it. While he is a worker like everyone else, he commands respect from everyone in the way he treats people. Slim shows sincerity to all with whom he interacts, including outcasts like Crooks, Candy, and Lennie. Unlike Curley and the other bosses who use their position of power to demand respect, Slim works with others and commands it. In both dynamics, Steinbeck seems to be making a suggestion about how management can only be worthwhile when it has a stake in the operation. When management is a part of production as opposed to distinct from it, a greater harmony emerges. Curley remains distinct from the other men on the ranch, a barrier of entitlement precluding his full embrace of and by them. This is not what Slim demonstrates, showing full immersion in commanding the respect of the other workers.
Interestingly enough, there might be another and more flawed model of worker and supervisor shown in the workers themselves. Candy regrets his role of failed leadership in how his dog was dispatched. He communicates this to George in that he should have exerted leadership to one that looked to him in providing it. Candy represents failed leadership in how he refused to assert control of the situation with his dog. When George is confronted with the blinding instant of poignancy in what to do with Lennie, he asserts leadership to one who looks to him in giving it. When Lennie asks him one last time to tell him about the farm and their dreams, George obliges, assuming leadership in the most brutal and painful of ways. He asserts leadership, though he is broken to do so. This is represented by the fact that Slim is the only one who can comfort him. Here again, Steinbeck demonstrates how true leadership is one in which worker and supervisor are not entirely distinct from one another, but rather linked in multiple ways to one another.