Okonkwo is frustrated by Nwoye because he reminds him so much of his own father, Unoka. Okonkwo is disappointed that Nwoye resembles Unoka in that he's sensitive and often lazy. Okonkwo views these as signs of femininity which he believes is one of the most disgraceful traits an Ibo man can display. Because of this, Okonkwo is constantly criticizing and even beating Nwoye in hopes that it will help him become more masculine and less humiliating to his father. When Ikemefuna comes to live with their family, Nwoye begins to demonstrate more masculine behavior which makes Okonkwo proud, although he never admits to it. Nwoye develops a strong brotherhood with Ikemefuna and remembers their three years together as the happiest time in his life.
When the oracle decides that Ikemefuna must be killed, Okonkwo ends up being the one to follow through with the order. Nwoye is enraged and devastated by the murder of his brother. He develops an anger towards his father that never dissipates and eventually leads him to convert to Christianity when the Europeans arrive and begin to colonize the villages.
Nwoye hates Okonkwo because of Okonkwo's action towards family members, and his strive to be perfect. Because of his childhood, Okonkwo wants to make sure that he and his family are perfect, thus putting a lot of stress on Nwoye who resembles more of a carefree person. Also later on Nwoye becomes friends with Ikemefuna, but later on Okonkwo himself was the one that killed Okonkwo. Nwoye knowing the fact makes him wonder both his faith and his father's views.