If you prick us do we not bleed? If you tickle us do we not laugh? If you poison us do we not die? And if you wrong us shall we not revenge?
William Shakespeare

There are minds so impatient of inferiority that their gratitude is a species of revenge, and they return benefits, not because recompense is a pleasure, but because obligation is a pain.
Samuel Johnson

Revenge is an act of passion; vengeance of justice. Injuries are revenged; crimes are avenged.
Samuel Johnson

What I do, I do not because your actions have endeared you to me, nor because your actions have enraged me. What I do, I do because I hold to the concept of retribution. I act because you have earned it thus, and not for any petty emotions.
MLRO