Sometimes being polite is perceived as being rude. Balancing formal and informal roles in organizations is a delicate matter. And in certain situations, one must develop a sensitivity to when a dispute falls into the realm of legal issues. Those who communicate with tact in such complex situations have learned that „it is not the facts that hurt, but only the communication“ (Niklas Luhmann). They know how to play with social expectations, how to address sensitive issues, how to gauge touches and physical distances, how to overlook embarrassing blunders of their counterparts, how to diplomatically override hostilities or communicate them only indirectly in order to avoid open conflict. Tact can thus be understood as a cultural technique to control the problem of (in)communicability and to mediate the abstract constraints of the context with the logic of a specific situation. This talk examines the forms and functions of tactful and tactless communication from a systems and media theory perspective and illustrates its communicative logic. What problems does tact solve? What are the advantages of being tactless? When does tactful communication reach its limits? And how does it become dysfunctional? In the context of these questions, the lecture outlines a general sociology of tact and tactlessness.