Nwoye had converted to Christianity, forsaking the gods of his father and his father before him.
Okonkwo disowns Nwoye after he joins the Christians, claiming Nwoye is no longer his son, no longer his children's brother. Okonkwo tells his children, "You have all seen the abomination of your brother."
The book does not say this explicitly until Nwoye joins the Christians, when Okonkwo calls him an abomination. However, Okonkwo often wishes that Nwoye was stronger, saying that at his age, he should already have impregnated a wife and taken a farm. Okonkwo also wishes that Nwoye were as strong a wrestler as Obierika's child, Okafo.
Okonkwo disowns Nwoye when he converts to Christianity. Okonwko originally assaults Nwoye when told of Nwoye's association with the Christians, resulting in Nwoye leaving the compound and joining the Christians.
Nwoye initially felt fear and intimidation in response to Okonkwo's confrontations. However, as time passed, Nwoye began to distance himself from his father's harshness and eventually disassociated himself from Okonkwo and his beliefs.
Ezinma was Nwoye's half sister. Both of them share the father of Okonkwo, but Ezinma's mother is Ekwefi; Nwoye's mother is Okonkwo's first wife.
Okonkwo's first wife's child was Nwoye, so she had a major influence on raising Nwoye, whether it be suckling from her breast, or originally birthing him.
Okonkwo tells his remaining children that he is ashamed of Nwoye for joining Christianity and warns them not to follow his example. He emphasizes the importance of traditional values and cultural beliefs, urging them to stay loyal to their ancestral traditions.
Nwoye denies that Okonkwo is his father after Ikemefuna's death, as he is deeply affected by the event and begins to question his relationship with his father. This moment marks the beginning of Nwoye's alienation from Okonkwo and his traditional beliefs.
Okonkwo chokes Nwoye. Be careful of your misplaced modifiers.
Cousin of Okonkwo. He tells Okonkwo that Nwoye has been to the Church in Mbantu.
Okonkwo threatens to break Nwoye's jaw because Nwoye has converted to Christianity, which goes against Okonkwo's traditional Igbo beliefs and values. Okonkwo sees this as a betrayal and a threat to the family's honor.
Subjective answer: The thing that upsets Okonkwo the most internally, is the fact that Nwoye is too much like his grandfather Unoka. The one action that gets Okonkwo the most upset externally is finding out that Nwoye has been hanging around the Christians, at which point Okonkwo confronts Nwoye and nearly chokes him to death.