Pierre, micaela, and jon are friends, but pierre and micaela are much closer to each other than either of them is to jon. why do they stay friends with jon at all? the concept of triadic closure suggests that:

an informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.