I lived my undergraduate years in a women’s dormitory with community-style bathroom facilities. I soon found that taking a shower in the morning was a statistical impossibility. Each floor of about fifty women had two bathrooms with three working showers each, which is a ratio of approximately eight people to one shower. If I wished to take a shower in the morning, I would have to wake up much earlier than I normally would have. Even then, there was no guarantee that a shower would be available and there was a great possibility I would be late for class.

I soon learned to keep my ears perked for the sound of wet flip-flops squeaking on linoleum. When I heard my opportunity, I would make an Olympic qualifying sprint down the hall, all while hoping the girls in the room adjacent to the bathroom were still asleep. Growing tired of this, I decided to take a different approach. I had noticed almost no one used the showers late in the evening. One could take a shower for as long as needed and without any fear of hot water running out. From that point on, I showered exclusively late in the evening and never had to fight for a shower again.

My experience with dormitory showers is an example of the congestion strategy game. The “right” choice is a morning shower and the “left” choice is an evening shower. As more people took a morning shower, the payoff decreased since I had to wake up early and could be late for class. Seeing an opportunity to avoid a reduced payoff, I chose to take a shower in the evening.

Had the payoffs for each shower time been symmetrical, more people would have defected to evening showers settling at the collectively superior equilibrium. This equilibrium would have reduced the problems created by too many people taking showers in the morning. However, it is clear that the two payoff curves were not symmetrical. Most people continued to take morning showers and the collectively superior point was never reached because the majority continued to pursue their self-interest.