After reading Hokage's views on Uchiha Sasuke:
Human nature is dissatisfaction, hatred is that you or they have seriously violated our dissatisfaction and the right to pursue happiness, and it is hatred that arouses my or our hostility. And when this severity reaches a certain change, it will cause a qualitative change, which will give us the motivation to kill or even kill.
Relatives-the source of hatred
How he hoped that what happened that night was just an illusion. How much he hopes to see his beloved relatives when he wakes up. Everything came suddenly, and he couldn't accept this fact for a long time. But the facts always tell him cruelly: his home is gone; his parents have passed away; everything about him is lost.Naruto Shoes Jordan
It is because of cherishment that I feel painful when I lose it. His heart is still changing. He began to pursue strength. He wanted to avenge his lost loved ones. He wanted to prove his existence. He wanted to cut off unhappy enemies and turn grief into strength.
Fatal emptiness
There is no fetters of relatives, no thoughts of relatives, no existence of pursuit. This is undoubtedly a fatal emptiness for a child who is only 8 years old. He began to miss his previous life and his lost loved ones-endless loneliness made him jealous of other people's happy families. This was the beginning of a psychological change.
Chain of Hatred
The chain of hatred began, he lost everything, their hatred continued to rise, and they began to feel unbalanced. He wanted to kill everyone. He hates this world. He spread hatred. He wanted the relatives of those who were killed by him to understand his feelings, and for those people to try to fear and to suffer. In this way, their psychology can be happy. He started to go crazy.
A fallen heart   Naruto Akatsuki Shoes
He seemed to understand his hatred, but he couldn't stop it. There seemed to be a voice in his heart telling him: How did your relatives die and what it looked like... He was powerless to resist, he always felt that killing those geniuses would liberate the souls of the dead relatives. Although his alarm clock is still sensible, his extremely empty heart is occupied by hatred, and he is unable to resist.