Sasuke started out as normal as anyone else, happy and care free. His mother was good and loving. His brother was like a best friend and idol to him. His father was someone to be respected. Everything was fine. Good even. Then, little by little, he began to slip away from the people who once considered him friend. After all, they were only getting in the way of what he wanted: to surpass his brother in any way he could find. Then half of his world was ripped away in the form of the elder being the primary focus until he left. What was left of their father's ideas were abandoned as though his younger were simply incapable of doing the same task. If asked about it, he replies he doesn't know why. But this is all lies to protect from the hurt and the tears that he had never let himself fully experience. Yes, their figurative loss hurt him and in a way changed who he was for the rest of his life, but he wasn't about to show weakness in front of others. That would have been disgraceful.
All through the school years and despite the lack of actual attention from his parents , he grew up a little too fast for his own good, believing he didn't need to lean on anyone, seeing it as a weakness. He wouldn't do that. There was no way he would do that. There were times, however, he secretly wished he could, but he'd never let himself divulge this information. The teachers began to worry, but what could they do, right? What was left of his family was stable, secure and could manage for himself.
In a way, he blames his older brother, though Itachi had nothing to do with it. Perhaps it made him feel better to have something concrete to hate. Something to keep him motivated to seek out his revenge against whoever the true suspect was.
After graduation, Sasuke had saved up enough money to get a small apartment for himself, applied for near by colleges, though he could have gone anywhere he chose. After all, keep your friends close and your enemies closer, right? He chose to go to a college that was middle of the road in distance, saving money from his wages and tips with the help of scholarships and things like that. But, at least the criminology department was rated in the top twenty of the country. He was bound and determined to get his revenge.
Everyone knew his reasoning for going into the field that he had chose. Everyone knew that it was still his biggest grievance, though no one asked and he never acted like it bothered him still. It was the only evidence that seemed likely.