Institutional economists concerned with rules often focus on the trade-off between individuals and social incentives. This paper argues that the real trade-off that individuals face is between the organizations they belong to in contrast to social rules, and asks when do individuals find it in their interests to act in the interests of their organizations and when do they support impersonal rules? The answer involves a distinction between anonymous relationships between individuals who do not know each other personally, but know the organizations that the other belongs to, and impersonal relationships in which all individuals are treated the same.