Revenge is a dish best served cold.

How many times has someone done something to infuriate you and your reaction has simply made matters worse? The old advice of counting to ten before reacting can save you from a serious breakdown in relations. "If you give them enough rope they will hang themselves" goes another old saying indicating the wisdom sometimes of not hitting back immediately. If you do have to take defensive retaliatory action it is best done when you are calm and rational.