Sforno interprets the idea of “this evil,” to mean the performance of bad in return for good. Yosef’s prime concern was the gratitude he owed his master. He could not respond to the advances of his master’s wife because of his hakoras hatov, the appreciation he felt to Potiphar. We may infer from here a lesson regarding the significance of hakoras hatov, and how far one must go to fulfill his obligation to acknowledge gratitude. Yosef was subject to the blandishments of Potiphar’s wife on an almost constant basis. She tried to entice him in every way possible. She would speak to him affectionately; she varied her mode of dress; she threatened him with prison and humiliation; she threatened to blind him; she even resorted to offering him a bribe. He ignored her threats and rejected her offers due to hakoras hatov. He acknowledged the good that Potiphar had done for him. Thus, he adhered to his obligation to be makir tov. He was willing to suffer pain and humiliation, all for hakoras hatov. Why? What did he really owe Potiphar? He had a job. Potiphar needed a manager and Yosef was available. Does Yosef owe Potiphar that much gratitude? One would think that the opposite makes more sense; Potiphar owed Yosef! Indeed, Chazal tell us that originally Potiphar made Yosef work very hard. Only after he noticed that everything Yosef touched became blessed, did Potiphar relent and grant Yosef a prominent position.
Horav A. Henoch Leibovitz, Shlita, remarks that regardless of the motivation of the benefactor, the obligation to recognize and appreciate the good one receives demands reciprocity. Yosef owed Potiphar hakoras hatov even though Potiphar was not worthy of it. Potiphar’s worthiness, however, is not an appropriate standard. We always look for reasons to justify our lack of appreciation to others. If we would realize that our attitude towards others defines our own menchlichkeit, human decency, we might be able to train ourselves to have greater respect for others.