In Things Fall Apart, Okonkwo's rashness is a character trait that he cannot seem to change. Chinua Achebe suggests that he is a tragic hero, because his flaw is innate and sparks numerous events with negative consequences. Some of Okonkwo's hasty actions do not have immediate repercussions. Those that occur early in the novel largely serve to establish his personality and related behaviors and to provide foreshadowing of larger problems to follow.
One such hasty action occurs when Okonkwo beats his wife Ojugo for neglecting her domestic duties. Because this occurs during the Week of Peace, he must pay a fine. The relatively small consequence does not dissuade him from similar behavior—as he later beats his other wife, Ekwefi. The repercussions of this action are much greater. Initially, nothing happens to him, but he has hurt Ekwefi emotionally as well as physically.
When he overreacts again by shooting at her during the festival, that is when he accidentally kills Ezeudu's son. This action does have serious consequences: Okonkwo is banished. Although living away from his community for seven years does have some positive benefits, the banishment is the beginning of the end for him. It essentially alienates him from the developments going on there. When he returns, he is like a stranger in his own home.