It could be that Harry has grown tired of the political games in the wizarding world. He sees all the power - hungry people around him and just can't take it anymore. So he tells everyone to get stuffed and sets out to create a new kind of community or way of life. He might start to gather like - minded individuals who are also fed up with the status quo.
It could be about Harry being frustrated with everyone around him and finally lashing out with the 'get stuffed' attitude. Maybe he's tired of people's false pretenses or constant demands.
Luna could be in this fanfiction. She would probably have a very unique perspective on Harry's actions. She might see it as a sign of Harry breaking free from the norms that have been confining him. And Neville could also be there, perhaps being one of the few who understand Harry's reasons on a deeper level.
Obviously, Harry would be the main character. There could also be his friends like Ron and Hermione. And perhaps some of his enemies like Draco Malfoy or other Slytherins.
In this kind of fanfiction, perhaps Harry feels extremely lonely. He might start to doubt himself and his worth. Maybe he tries to find ways to get noticed but always fails. For example, he could be left out of group activities at Hogwarts, and his friends seem to not care about his presence anymore. This could lead him to explore new aspects of magic on his own, away from the usual crowd, and in the process, he discovers some hidden powers or secrets that eventually make others realize their mistake of ignoring him.
Well, it could start with Harry being wrongly accused of something major, which leads to everyone abandoning him. He then embarks on a solitary journey to find the truth and clear his name. During this time, he might encounter old enemies who see his vulnerability and try to take advantage of it. However, Harry's determination and the few skills he has managed to retain despite the abandonment help him fight back. He also has internal battles with feelings of loneliness, betrayal, and self - doubt, but ultimately he rises above it all to show that he is still a force to be reckoned with.
One possibility could be that Harry is under some dark magic influence. Maybe he's been corrupted by a powerful and evil spell or artifact that makes him lose his sense of right and wrong, leading him to turn on everyone. Another aspect could be that he's been betrayed so deeply by those he trusted that he snaps and decides to take revenge on everyone, believing they are all against him.
Maybe Harry has had some really bad experiences that made him bitter towards everyone. For example, he could have been betrayed by his friends multiple times.
Well, perhaps in this fanfic, Harry could be wrongly accused of a serious crime like dark magic use. Everyone, including his friends Hermione and Ron, might turn their backs on him due to false evidence. He would then have to fight alone to clear his name and find out who really framed him.
Perhaps the plot could revolve around a magical accident or curse that makes Harry lose his ability to feel positive emotions towards others. As a result, he starts to hate everyone. He begins to act out against the people he once cared about, causing chaos in Hogwarts and the wider wizarding community. His friends would be shocked and try to find a way to reverse the effect, but Harry would resist their attempts.
Well, perhaps Harry is frustrated with Dumbledore's secrets. Maybe he's angry about being kept in the dark regarding his own fate or the danger around Hogwarts. So he decides to confront Dumbledore and let out all his pent - up feelings.