In game of tragedy of commons, every individual tries to reap the greatest benefit from a given resource (usually a common resource like lake, river etc.). As the demand for the resource overwhelms the supply, every individual who consumes an additional unit directly harms others who can no longer enjoy the benefits.
Examples are not hard to find. During good times, every departmental head tries to expand his team as “resources are badly need to keep business running”, with no regard to its overall impact on manpower plan of organisation, soon there is over staffing esp. if good times are followed by recession or stagnation. Reluctance to downsize means poor bottom line, lesser hike and high attrition.
Pollution of our lakes, rivers, seas, atmosphere etc. are example of tragedy of commons, each industrialist releases untreated effluents, till entire lake/river gets polluted, impacting livelihood of entire population that is dependent on lake/river.
There is one more phenomenon; it is called social loafing/free riders. Some people try to take advantage of common resource by not paying anything, as others are contributing anyway.
Good example is game of tug of war. Some players refuse to put any efforts, so burden of pulling rope falls on sincere players. Some team players indulge in loafing, as other members will finish the task anyway.
In Economics, while tax payers’ contribution results in roads, water supply, electricity etc., some free riders ex. slum dwellers enjoy such common benefits free of cost. Soon this pilferage of water/electricity results in bursting of pipes/bringing power gird down- result is entire population suffering.