I do not own Naruto.
Itachi always wondered what it was like to die. Hell, he was always the one that did the killing it wasn't like he had ever been in a real life or death situation. But the second he walked into his home he remembered. To die was to lose all self-control, to have no control over what happens to you. He knew what it was like to die but not truly.
At home he was a tool. Not truly a person so no true human value. Right? Was that what he was? To the clan he was a way to advance themselves. To his immediate family he was like an object of great value, something to show off and hold and control tightly. In reality if he thought about it he really didn't have control of where his life would go. It would be his parents who eventually chose his wife, his clan who decided what he should do with his career.
Oh yes Itachi harbored thoughts of suicide and homicide. They build up with the anger in his heart fueling it. Was he disgusted with his imagination? Yes, he kept them bottled up inside till it was almost too much. He buried his wants and desires till he wasn't even sure they were there. But they had been and they would lash out during missions resulting in his sudden violence. Don't we all want to pretend everything is alright? Of course, Itachi deceived himself into thinking there was an end to his pain. There was a way out the sweet and rewarding severing of ties or the pain and relevance of death.
Living with his family was like losing himself. The expectation, was suffocating and pressing him on him. The false smiles were the catalyst of his anger it fueled the beast inside him. The longer he stayed where he was the more he wanted to leave, the more he tried to convince himself this was where he belonged the more he felt it wasn't.
He always felt that adults were luckier. They had no true ties, nothing holding them back from leaving. But even adults deluded themselves into thinking about family ties and bonds that couldn't be broken. Tch, they were meaningless as far as Itachi was concerned they held him back. To break them would mean freedom. Kids could only wait for themselves to grow out of the ties or sever them themselves and it wasn't easy to wean yourself from something that offered stability even if it was false assurance. It took too long to grow up, you waited year after year of living a life you don't want. Itachi chose to sever those ties. And from what was lost he gained himself.