When 1st introduced, Sasuke Uchiha had a ton of potential as a dark, revenge-imbued character. As an Uchiha, he is loved by everyone, especially girls. However, as the time goes, he became one of the most polarising manga/anime characters of all-time. As Naruto progress throughout the years, many readers/watchers despise Sasuke, so let's take a look on how this Uchiha became the most hated character in all of Shōnen.

HIS CHARACTER PROGRESSION

Now, I think this is something most of us can acknowledge: his problems w/his character progression. Let's take a look at Sasuke's development after Itachi's death:

• First target Elders/Danzo, even if he has to burn through Konoha
• Through flashbacks, this becomes burn all of Konoha which he apparently kept hidden from his own team because Suigetsu, Karin & Jugi are SO MORALISTIC & LOVE KONOHA
• During the Killer B fight there is an "Amaterasu of friendship'" where he thinks of Team 7 while saving Taka PLUS he is fairly calm & "normal" for Sasuke during this
• Then comes the Kage arc where he suddenly for no reason goes "MU-HA HA HA HA, I am so evil and insane & willing to sacrifice my own team mates who saved my life."
• Then he suddenly becomes semi-sane again for no reason after leaving that cave because Kishimoto needs a semi-sane Sasuke to talk w/his brother.
• Almost forgot this: 1st he says that he does not want Itachi's eyes as he will see/do things differently then what his brother wanted. He then changes his mind super-fast & takes Itachi's eyes & wants to honour his brother's wishes
• Then comes the Hokage meeting where he doesn't ask the hard questions/even try to get the other sides & even appreciates DANZO of all people
• Then Sasuke suddenly wants to become Hokage of all things (which brings a bloody annoying scene where everyone wants to become Hokage for 5 minutes)
• Then Sasuke apparently forgets his "vengeance" against Obito for no reason when he could have killed the guy right there & then
• Then Sasuke, the guy who went out of his way to gather: Karin, Suigetsu & Jugo because he needed back up against Akatsuki suddenly forgets team work because Kishimoto wants to again make a point despite the fact that Sasuke already knew the stupid point
• Then Kishimoto gives Sasuke 1 of the stupidest reasons to fight Naruto that I have heard all because Kishi wants a final fight between the two.

So, Sasuke did not have so much character development after Itachi's death. He just had Kishimoto throwing him whichever way would make it easier for Kishi to write a story. Sasuke is like a blank slate that changes within a blink of an eye. Sasuke's character suffered a regression when he was not supposed to. Kishi just kept changing the story so much that no real progress was made down any of those paths.

HIS MOTIVATIONS

Even after he sorts all this nonsense out w/his resurrected brother & learns the true reason behind Itachi’s actions (trying to prevent war), his motives were still irrational & overly emotional. His final authoritarian goal to stop war through fear is dumb. He wanted to kill all leaders & put himself up as a common enemy people will hate together, who else can see where this plan might go wrong? (like him dying for one!) It becomes so convoluted that it takes losing an arm to make him realise how dumb it is & even then he only submits because Naruto is more childishly stubborn about his ideals than he is. To sum up, 1st, he wanted to be in the village & learn, then he wanted to leave the village to be w/Orochimaru, next he wanted to kill Itachi, then he wanted to be hokage & destroy the place that Itachi wanted to be safe. He had "friends", then he tried to kill said "friends." So, Sasuke is somewhat like "I'm gonna kill Itachi because he killed my clan!" BUT he doesn't know the context behind it BUT he still act like he DOES know the context. That's why it's quite obvious why people would despise him.

HIS CHARACTER INCONSISTENCY

After Itachi shows how weak Sasuke is (& Gaara before him), we begin to see how irrational Sasuke is in his desperation get the strength he needs to kill him. This is where the inconsistencies w/his character begins to reveal themselves. In the later parts of the first series, Sasuke's emotions completely take dominance & undermine his reason. Even after learning that Itachi's actions were for the greater good of the Hidden Leaf, instead of following his path, he decides that redirecting his hatred & revenge at the people Itachi worked with and starting an all out war is the better option. Although these are all good examples of Sasuke doing something incredibly stupid from being overly emotional, he doesn't go fully crazy until he decides to support Madara's war EVEN after learning of Itachi's motive for killing the Uchiha and what he sacrificed to prevent such a thing. Despite his motivation to stop war/maybe even because of it, Itachi doing what he did was a dick move considering its consequences. However, not only was Sasuke blind to this fact & began fighting to avenge him, but he was also blind to the fact that by avenging Itachi against Konoha he was causing the very thing Itachi died trying to prevent. To put the cherry on the cake, even after Sasuke learns that Obito lied to him about Madara's involvement in the 9-Tails invasion, it doesn’t put a dent in his resolve, despite this showing that it was really him who caused the Uchiha coup & in turn, their destruction.

HIS PERSONALITY

Sasuke's personality is 1 of the many things why people hate him. He openly admitted like 2 times to Sakura (the girl he would ultimately marry) that she's "really annoying" & even tried to kill her & Naruto. Sasuke has both a superiority & an inferiority complex, as he is unwilling to acknowledge when someone is stronger than him, but obsesses when he believes that they are. He seems to can't accept loss (except that 1 final battle against Naruto). He's a jerk & is arrogant. He is always like "I'm better & stronger than you & you are a spec of dust beneath my fingernails & I refuse to acknowledge you & you're annoying me". What bothers us is that he does this to everyone, even those far more powerful than him. He is always filled w/hatred & the desire of vengeance. He had no regards for the life of his comrades who are the only reasons he hasn't been killed many times. These traits makes him seriously unlikable.

THE FIGHTS HE WON

Most of his fight victories are asspulls/pis. Virtually everytime Sasuke was in danger/in a fight he clearly can't win, some Deus Ex Machina shows up to save him/he magically gets a new, generic Shonen power-up, an example is during his fight w/Deidara. This is why some people can't stand his fighting too.

HE BEATS/KILLS INTERESTING CHARACTERS

He's responsible for killing interesting Naruto villains such as Orochimaru, Danzo, Deidara, etc. Orochimaru couldn't even bring his plans to fruition yet. & this is also another reason why people couldn't stand this arrogant, op Uchiha.

CONCLUSION

That's it for why I think people hates Sasuke Uchiha so much. To sum it all up, imho, Sasuke Uchiha was a generic revenge-motivated Gary Stu, who, through a convoluted twist, becomes a bad guy w/too many character inconsistencies to take seriously. Sasuke really is a testament of Kishimoto's rushed & terrible writing, both in its inconsistencies & its lack of set up for important plot points.

However, I gotta admit that I love how he turned out in Boruto: Naruto Next Generations. His personality changes, his demeanour changed, funny this is now that he's the second strongest ninja alive & has the power to back up his arrogance, he's as humble as everyone, they made him into a wondering ninja that reminds me a lot of Jiraiya. Only problem that I extremely despise his current hair. So, yeah. That's it. Thank you so much for reading. Much appreciated : D