As irrational as is it, revenge is a normal human behavior.
A study confirms that thoughts of revenge can be so pleasurable that many of us are willing to pay extra for it. PET scans of the brains of people contemplating revenge showed a positive correlation between the amount of activity in reward-related areas of the brain and how much a person was willing to pay for the revenge.
This just goes to show how our passions can interfere with rational behavior.
