A man once came and spat on Buddha, on his face... His closest disciple, Ananda... was red hot with anger. Buddha wiped his face and said to the man "Thank you, sir... You created a context in which I could see whether I can still be angry or not. And I am not, and I am tremendously happy. And you also created a context for Ananda : now he can see that he can still be angry. Many thanks - we are so grateful! Once in a while, please, you are invited to come. Whenever you have the urge to spit on somebody, you can come to us."... His whole being was saying that he was grateful, his whole atmosphere was grateful. He could not forgive himself now, what had he done? Spitting on that man - a man like Buddha!
Early the next morning he rushed back, fell down at the feet of Buddha, and said "Forgive me, sir, I could not sleep the whole night." Buddha said "Forget about it... and I cannot forgive you, because in the first place I was not angry with you. If I had been angry, I could have forgiven you. If you really need forgiveness, ask Ananda. Fall at HIS feet - he will enjoy it!"
–From The Book of Wisdom : Discourses on Atisha`s Seven Points of Mind Training