From Imitation of Christ:

Do not say: “I cannot bear this from such a man, nor should I suffer things of this kind, for he has done me a great wrong. He has accused me of many things of which I never thought. However, from someone else I will gladly suffer as much as I think I should.”

Such a thought is foolish, for it does not consider the virtue of patience or the One Who will reward it, but rather weighs the person and the offense committed. The man who will suffer only as much as seems good to him, who will accept suffering only from those from whom he is pleased to accept it, is not truly patient. For the truly patient man does not consider from whom the suffering comes, whether from a superior, an equal, or an inferior, whether from a good and holy person or from a perverse and unworthy one; but no matter how great an adversity befalls him, no matter how often it comes or from whom it comes, he accepts it gratefully from the hand of God, and counts it a great gain. For with God nothing that is suffered for His sake, no matter how small, can pass without reward. Be prepared for the fight, then, if you wish to gain the victory. Without struggle you cannot obtain the crown of patience, and if you refuse to suffer you are refusing the crown. But if you desire to be crowned, fight bravely and bear up patiently. Without labor there is no rest, and without fighting, no victory.

[resources: The Imitation of Christ (highly recommended)]