Likely Okonkwo's biggest motivation is that of trying not to be seen as his father was, a weakling or a failure. This drives him to work incredibly hard, to fight like a lion and acquire two titles and become the veritable big man on campus in Umuofia. It also contributes to what is likely his biggest flaw, his single-mindedness combined with a wicked temper.
He is unable to think outside the bounds of Igbo culture.
I hope it helps :)