According to the humanistic psychologist people seek to reach their fullest potential. this idea is similar to the proposal by the neo-freudian that people strive for superiority.

Abraham Maslow and Alfred Adler

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.