How can one deal with a person who remembers the mistakes of others while forgetting their favors, and hunts for their slips even though he may commit similar ones?

The characteristics of mentioning and hunting for others' mistakes, forgetting their favors, and delighting in making them feel guilty are contrary to fairness, justice, and good morals. The true Sharia calls for forgetting one's own good deeds towards people and remembering their good deeds, and forgetting their mistakes while remembering one's own, and meeting injustice, deprivation, and estrangement with forgiveness, giving, and connection. This is based on the Almighty's saying: "And they repel evil with good," and "Repel evil with that which is better," and the Prophet's (peace be upon him) saying: "Shall I not tell you about the noblest morals of this world and the Hereafter: that you forgive him who wronged you, give to him who deprived you, and connect with him who cut you off."