One useful rule of thumb is to give positive support to the human beings on the other side equal in strength to the vigor with which you emphasize the problem. This combination of support and attack may seem inconsistent. Psychologically, it is; the inconsistency helps make it work. A well-known theory of psychology, the theory of cognitive dissonance, holds that people dislike inconsistency and will act to eliminate it. By attacking a problem, such as speeding trucks on a neighborhood street, and at the same time giving the company representative positive support, you create cognitive dissonance for him. To overcome this dissonance, he will be tempted to dissociate himself from the problem in order to join you in doing something about it.