first to the creator of this thread, why ask if you are just going to argue? you said you wanted peoples reasons, but seem to be trying to disprove them to fit your view. You wanted opinion, not facts...
sasuke has always been one of my least favorite characters. His atitude rubbed me wrong from the begining, and he only got worse. He was an arrogant show off. He seemed to think that having the best record in the academy, and being an uchiha made him automatically better than everyone else. This can be partially blamed on his family, and how the village treats him, but he didnt HAVE to let it go to his head. He could have been humble about his skills. He could have asked to be seen as just any other person. He supposedly looked up to Itachi, who didnt exactly appear to be arrogant and boastful in the flashbacks(other than the massacre, where he WAS arrogant), so he could have kept that example.
And before you say it, he supposedly hated Itachi after the massacre, yet still listened to him. Itachi told him to live a life of hatred to get stronger, and he does just that. He doesnt look to anyone else for advice on how to get strong, just follows what the murderer of his clan tells him to do....
After he got his Sharingan, he became even worse. He seemed to think he was invinceable. He also seemed to think that everyone elses hard earned skills should be just given to him, something which Kakashi seemed to agree with. While i personally dislike the Sharingan, i would have no problem if he used it on Enemies. But he stole from allies, which is just not cool.
His running off to Orochimaru for power was something that i saw coming, as it fits with his personality, but it still made me like him less. He could have gotten stronger in Konoha. He could easily have gotten just as strong as he did outside of Konoha, but he wanted a quick easy way to power. he didnt want to EARN power, he just wanted it given to him. That i think is my biggest problem with him(and naruto too, who we never really see trying to improve himself outside of assigned training, though he does woork his butt off with that training...). If he EARNED the power he has, i might still dislike his personality, but i would at least be ok with his abilities.
The mangekyou(sp?) just makes it worse. Its supposed to be the guilt from killing your best friend that brings out the mangekyou. His was just passed to him by Itachi. And he just keeps getting power ups, because his "Hatred" gives him power?
And his latest twists, wanting to destroy Konoha because 4 people in it, two of whom are dead ordered Itachi to kill his clan. Knowing how much the village adores the Uchiha he could easily turn the village against the elders. He instead thinks that the people who had no idea what happened should die for it?
Another problem i have with him(and Naruto) is how easily he believes what ever he is told, unless it contradicts what he wase told earlier. Sasuke is lead so easily by stoking his desire for power its not funny. For a supposed genius, he doesnt really think all that much for himself.....
Anyways, those are most of my reasons. His apparent homosexuality doesnt bother me so much. The apparent ease with which he can throw away his friends does.
Oh and seriously, how exactly did he plan to get the mangekyou from killing Naruto. The way he explained it he would need to feel guilt, and i dont think he would. He'd feel happy at finally having his mangekyou, and anger if it didnt manifest, but he didnt seem to actually consider Naruto a friend, much less his best friend. There is more to friendship than just saying "You are my best friend." and haveing a desire to murder someone for your opwn benifet doesnt really fall into that i dont think....