A social dilemma is a problem that occurs when an individual benefits from selfishness at the expense of the group. The main time that this strategy may fail is when the entire group employs this reaction in which case the entire group loses out.
One example of this would be a sports team where one player “seeks the spotlight” at the expense of his/her teammates and perhaps to the detriment of the entire team. Hypothetical social dilemmas are often used in research or discussion such as the Prisoner’s Dilemma.