Grazing created a negative​ externality, resulting in the commons being overused. Right! The commons ended up overgrazed. For​ example, a family thinking of buying another cow and grazing it on the commons would gain the benefits from increased milk​ production, but adding another cow to the commons would create a negative externality by reducing the amount of grass available for the cows of other families. Because this family - and the other families in the village - did not take this negative externality into account when deciding whether to add another cow to the​ commons, too many cows were added. The grass on the commons was eventually​ depleted, and no​ family's cow got enough to eat.