Would you rather be alone for the first 6-12 years of your life and find people that love you and be happy for the rest of your life OR be happy the first 7 years of your life and then be lunged into complete loneliness forever afterwards? Sasuke making his life goal to kill his brother sounded more to me like he never had a life goal. He always wanted to be like his brother so how was he supposed to handle what happened? He didn't have anyone there to verify that for him and because of that he got so convinced that what he was doing was the right thing to do and when everyone around you becomes powerful he was pushed into doing that. It's like he was pushed into drugs, think of it like that. Gaara is a good argument for this but I really don't think Naruto should be considered in this.