Why does okonkwo act as he does?

Okonkwo was generally unsympathetic to people because he had worked hard and believed that anyone who was not succeeding was doing so due to lack of trying. He did not believe those people were worth much. Okonkwo is occasionally sympathetic, but his need to be seen as a man leads him to behave impassively and with hard emotions like anger, but without soft emotions which would show weakness.