Yosef does not seek revenge against his brothers.
We can learn from the example of Yosef towards his brothers that one should never seek revenge against a person who causes him any form of distress or damage. Rather, one should repay even a guilty offender with kindness (Tanya ch. 12).
Why should we be kind to guilty offenders?
Because whatever that person did to you ultimately stems from God. The person was merely an agent from God, Who decreed that this thing should occur to you. Thus, since “everything that God does is for the good” (Brachos 60b), you must repay the person—who brought this “good” to you—with kindness.
(Based on Likutei Sichos vol. 5, p. 247)