In the fanfic, Harry Potter could meet the new generation of students. They would be in awe of him. He might also encounter some of the ghosts, like Nearly Headless Nick, who would surely have some interesting stories to share since Harry left. And there's a good chance he'll meet the caretaker, who would probably give him a hard time about coming back and causing a stir. Moreover, he could cross paths with some of the older students who idolize him and want to learn from his experiences.
It might be significant as it shows the deep engagement of fans with the Hogwarts setting. By reading fanfic set in Hogwarts, they can further immerse themselves in the magical world, experiencing different scenarios, relationships, and adventures that are created by fellow fans.
Maybe he hates it because it often distorts the real story or characters he knows. Fanfics can take the story in wild directions that don't align with his own experiences.
Well, in some fanfics, the idea that Hogwarts is a horrible school might come from a different perspective. Maybe the author wants to explore the dark side of the school that wasn't fully shown in the original books. For example, the strict rules could be seen as overly oppressive to some characters in the fanfic.
One possible reason could be that he feels constantly in danger at Hogwarts. With all the dark magic threats and attacks that keep happening, he might think leaving would keep his friends and himself safer. For example, after the Chamber of Secrets incident, he might have considered leaving to protect others from Voldemort's influence.
One possible reason could be misinformation spread by the Ministry of Magic. They might have spread false rumors about Harry being a threat, which influenced the Hogwarts community. For example, if the Daily Prophet printed false stories about Harry's supposed dark magic activities, it could turn some students and staff against him.
There may be some fanfics out there with this premise, but it goes against the general relationship dynamics in the official 'Harry Potter' universe. Usually, Harry respects and values Hermione. If such a fanfic exists, it might be written by someone who wants to explore a really dark or different side of the story, like if there was a major event that made Harry turn against Hermione in that fictional narrative. But I haven't actually come across one myself.
One possible reason could be a miscommunication. Maybe Hermione accidentally reveals a secret of Harry's that he didn't want known, and this causes him to feel betrayed and start to hate her. Another reason could be jealousy. If Hermione gets more attention or praise for her magical abilities than Harry in the fanfic, he might develop feelings of envy and hatred. Or perhaps there's a love triangle situation where Hermione is involved with someone Harry doesn't like, and that causes his hatred.
Harry might initially be shocked and confused. He's used to Hogwarts being his safe haven, so when it turns against him, he'll be at a loss. He may try to prove his innocence by finding evidence or confronting those who are spreading lies.