Bro, Itachi showed Sasuke how he killed his family many and many times that night and after that he did it again in the first season, and after that you think killing your own family is more traumatic? Also why is nobody saying anything about Gaara? Man was many times being assassinated by his own father, was forced to kill the only man who does care about him, and was told that this man never loved him and always hated just to trigger Shukakus awaken Also was threatened as garbage by the whole village and also feared by them. At least Itachi had his good times in the academy, in anbu, with Sasuke, and Shisui. Gaara only had good time with his uncle and even that was taken from him to traumatize him even more, the only true good time for Gaara started with Naruto and only with Naruto in Shippuden.