When, however, you have an enemy, then do not requite him good for evil: for that would shame him. Instead, prove that he did some good for you. And rather be angry than put to shame! And when you are cursed, I do not like it that you want to bless. Rather curse a little also! And if you are done a great injustice, then quickly add five small ones. Hideous to behold is he who is obsessed with an injustice.
Friedrich Nietzsche, Thus Spoke Zarathustra
morality, philosophy