Most system dynamicists have used the example of a simple shower to explain feedback and to introduce the cyclical dynamic behaviour characteristic of a balancing loop. The damped system's temperature is relatively easy to manage. But with two showers sharing the same limited supply of hot water it is much harder to control the water temperature, because a person “managing” one shower is unaware of the other, yet must react to the aggregate temperature outcome resulting from “joint management” effort. A system dynamics model of a two shower system is presented and is simulated to illustrate the causes and consequences of interdependence in resource allocation, and to explore changes that can improve the coordination of decision-makers. Insights from the two shower model are then applied to understanding coordination in multinational subsidiaries with overlapping geographical markets. The article ends with some reflections on the value and limits of a metaphorical model.