One reason could be a personal betrayal. Maybe a close friend from Gryffindor betrays Harry, and this makes him start to dislike the whole house. It's like when one bad apple spoils the bunch in his eyes.
It could be due to a misunderstanding. There might be a situation where Harry misinterprets the actions or intentions of the Gryffindor house as a whole. For example, if there is a Gryffindor - led initiative that Harry thinks is harmful, but in reality, it's just a miscommunication. This misunderstanding could fester and turn into hatred in the context of the fanfic.
One reason could be that the fanfic distorts the characters he knows well from Gryffindor. For instance, if it changes the personalities of his friends in Gryffindor in a way that doesn't seem right to him.
One reason could be that he doesn't like the spotlight that comes with being a Gryffindor. In the original story, Gryffindors are often in the limelight, and in fanfiction, he might be tired of all the attention.
One possible reason could be jealousy. Maybe Albus feels overshadowed by Harry's fame and achievements. Another reason might be some misunderstanding between them. For example, if there were miscommunications or false rumors spread about Harry that Albus believed.
It might be related to power dynamics. If in the fanfiction, James has a lot of power and misuses it in a way that affects Harry or those around him, Harry would hate him. For example, if James uses his influence to push through unfair rules or to marginalize certain groups that Harry supports. Also, if the fanfiction changes James's personality to be more self - centered and less empathetic, Harry would likely dislike him.
One reason could be a falling - out with his friends in Gryffindor. Maybe there was a misunderstanding that grew so large that he felt he couldn't stay. Another possibility is that he might be lured away by some mysterious force or character who convinces him that Gryffindor is no longer the right place for him. For example, if a new group claims to have a better way to fight Voldemort and they are from a different 'house' in this fanfiction concept.
In some fanfics, there could be a misunderstanding. Suppose Kushina did something that Naruto misinterpreted as harmful to him or his friends. This misinterpretation could lead to his hatred. For example, if Kushina was involved in a mission that Naruto thought put the village at risk, but in reality, she had no choice.
One reason could be jealousy. Maybe in the fanfic, Annabeth gets more attention or praise for her skills and Percy feels left out or overshadowed, which turns into hatred. Another possibility is that there's a rift caused by their different approaches to solving problems. If Annabeth's logical thinking clashes too much with Percy's more instinctive ways, it could lead to resentment.
One possible reason is that their personalities clash. Percy is often portrayed as a more outgoing and confident character, while Nico is more introverted and brooding. In a fanfic, this could lead to misunderstandings and animosity between them. For instance, Percy's bold actions might seem reckless to Nico, causing him to dislike Percy.
One reason could be that the fanfic changes the essence of their relationship. In the original, they have a certain dynamic that she values, and fanfics might mess it up.
Perhaps Female Harry Potter hates Dumbledore because he seemed to prioritize the greater good over her individual well - being. He sent Harry into dangerous situations, like facing Voldemort multiple times, without really considering how it affected her on a personal level. Also, Dumbledore's past actions, such as his association with Grindelwald, might make her question his moral compass. If she discovers this part of his history, she could lose trust in him and develop hatred.