In Achebe´s Things Fall Apart, Okonkwo finds his son Nwoye´s signs of laziness "disquieting" because it reminds him of his father
Even as a man, he remembers as a little boy how he suffered on hearing a playmate call his father, Unoka, was an "agbala" - a woman. His father´s gentleness and idleness made Okonkwo abhor anything that reminded him of Unoka. He believed that a man had to instill fear to be respected. In Umofia, the fearlessness in war was highly respected therefore, the love for war and violence were his governing spirit.
When he noticed his father´s traits in his eldest son, Nwoye, he becomes "disquieted" for he was ruled by one passion - hate everything his father had loved.
The answer is his father! He wanted to be different than his father because he was lazy and did nothing so when he sees this, all he can think of is his father!