Why is Nwoye happy to leave his father? How is the presence of the Christian missionaries adding to existing tension between Nwoye and Okonkwo?

Okonkwo is abusive towards his son Nwoye. He constantly berates Nwoye for being "feminine" and lacking strength. Consequently, Nwoye is glad to find refuge in the Christian church. The church challenges Igbo belief systems. They welcome ostracized people like Nwoye creating further tensions with the tribe.