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Revenge from WikiPedia:

Revenge (synonym vengeance) is a harmful action against a person or group as a response to a (real or perceived) grievance. Although many aspects of revenge resemble the concept of justice, revenge connotes a more injurious and punitive focus as opposed to a harmonious and restorative one. Whereas justice generally implies actions undertaken and supported by a legitimate judicial system, by a system of ethics, or on behalf of an ethical majority, revenge generally implies actions undertaken by an individual or narrowly defined group outside the boundaries of judicial or ethical conduct. The goal of revenge usually consists of forcing the perceived wrongdoer to suffer the same or greater pain than that which was originally inflicted.

In some societies, it is believed that the punishment in revenge should be more than the original injury, as a punitive measure.

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