Why does a mother differentiate in the treatment of her children, which arouses a feeling of hatred in a son despite his dutifulness towards her?

If a mother mistreats her children and shows favoritism among them, she is indeed in the wrong. However, she must still be honored and obeyed in what is right, regardless of her condition or mistreatment. The right of a mother is immense, and Allah has commanded accompanying even polytheist parents with kindness. One must beware of mistreating her by raising one's voice or speaking harshly. Instead, address her with politeness, gentleness, humility, and reverence, as Allah Almighty said: "So do not say to them [anything that indicates] disapproval and do not reprimand them but speak to them a noble word. And lower to them the wing of humility out of mercy and say, 'My Lord, have mercy upon them as they nurtured me when I was small.'" One must strive against their own self, endure with patience, and exhibit good character, for knowledge is gained by learning, and forbearance by striving to be forbearing.