While Sasuke did act as a douche, he did have a reason. His family was killed by his own brother who didn't reveal why he did it, and left him with pure hatred on purpose. He always looked down on Naruto in public, but in private he was envious of him. He may have been "better" than him in almost every way except heart, but to him Naruto was always one step ahead of him, just like Itachi used to be. It hurt him. Orochimaru gave him the cursed seal, and witnessing its power, he went with Orochimaru with hopes of gaining more power faster. In the end of the manga, he confesses that he started seeing Team 7 as a family at one point, and considered Naruto to be his friend, which is probably why he didn't kill Naruto after their first real fight(CS2 Sasuke vs Kyuubi mode Naruto), where he left his hidden leaf headband with Naruto. After finding out that Itachi did it all because Leaf village commanded it, and that he still loves Sasuke caused all kinds of emotions to stir up in Sasuke.
He then swore to destroy hidden leaf, but first he wanted to know all the details, hence the summoning of the four Hokages. That is when he realised that destroying Hidden Leaf isn't good enough. The world needs a revolution.
While Sasuke isn't the oochy-boochy good guy, he wasn't completely evil. Douche, but with reasons.
While Sasuke isn't the oochy-boochy good guy, he wasn't completely evil. Douche, but with reasons.