After Yosef revealed his identity to his brothers, the Torah tells us, "And he kissed all his brothers and wept upon them, and afterwards his brothers spoke to him" (Bereishis 45, 15). Rashi explains that immediately after Yosef revealed his identity, the brothers were too embarrassed to speak to him. Only after he calmed them down and kissed each one of his brothers were they able to bring themselves to speak to him.
Rav Wolbe (Shiurei Chumash) comments that Yosef's inner strength is astounding. Not only did he not harbor any ill feelings toward his brothers, he did all in his ability to ease their feelings of guilt: "It wasn't you that sent me here, rather, it was Hashem; and He has made me as an advisor to Pharaoh, a master over his house and the ruler of the entire land of Mitzrayim" (bid. 45, 8).
This interaction could have easily looked much different. Many people when they feel wronged wish to get even with the offender, and their revenge is directly proportionate to how high they have climbed up the ladder of success. If the person offended were to become a monarch, the offender would probably pay for the offense with his life. This was not the case with Yosef who, despite his supreme position, didn't mention a word about revenge. Moreover, the Torah tells us that Yosef's only consideration before he revealed his identity was that his brothers shouldn't be embarrassed. For this reason, before he identified himself he demanded that all the Egyptians leave the room - although such a request put him in mortal danger. "And no one remained with him when Yosef revealed his identity to his brothers."
Let's put ourselves in Yosef's shoes for a minute. Would we have the awesome inner strength to completely forgive someone who caused us so many years of hardship and anguish (G-d forbid); even if at the end of the day it turned out for the best? Most probably the answer is "no."
Avodas ha'middos - rectifying our character traits, is the most difficult avodah that faces a person. We know where we stand, and the Torah informs us what we must strive for, via the stories of the Avos and Shevatim. As Chazal tell us (Tana D'bei Eliyahu 25), "A person must say, 'When will my actions rival the actions of my forefathers."