One possible reason could be a misunderstanding. Maybe there was a miscommunication about something important, like a plan to fight against the Dark Arts. For example, if the Weasleys accidentally left Hermione out of a crucial part of the plan, she might be very angry.
It could also be because of a difference in values. If the Weasleys have a more laid - back approach to something like schoolwork or following rules, and Hermione, being a stickler for rules and academic excellence, might get mad at them for their lackadaisical attitude.
Perhaps Ron Weasley said or did something really hurtful to Hermione, and she extends her anger to the whole Weasley family because they are so close - knit. Like if Ron made a comment about her Muggle - born status in a negative way, Hermione would be justifiably mad at him and might be mad at the rest of the Weasleys for not correcting him right away.
Well, in many fanfictions, Percy might be seen as too ambitious and career - focused. He could have made choices that put his job at the Ministry above his family. For example, he might have supported Ministry policies that the rest of the Weasleys disagreed with, like their stance on Harry Potter or how they were handling the growing threat of Voldemort. This could lead to the Weasleys being mad at him for seemingly choosing the wrong side or not standing by the family values.
Well, they could start with an honest conversation. The Weasleys could sit down with Hermione and ask her what's wrong. For example, Ginny could take the lead and say, 'Hermione, we know you're mad at us. Let's talk about it.'
The Weasleys could also be the ones to reach out first. They might realize that Percy was in a difficult situation at the Ministry and that he didn't mean to cause them harm. So they forgive him and they all work together to face whatever threats are out there, like Voldemort's return.
It could be that in the fanfic's plot, the Weasleys have some actions that go against Hermione's principles. Say, they might be involved in some pranks that have negative consequences for Hermione's studies or personal goals, and that's why she hates them.
One possible reason could be jealousy. Maybe she sees the Weasleys as getting things too easily in the wizarding world compared to her own hard - earned achievements. For example, they have a big family support system that she lacks, and she might envy that.
Perhaps in this fanfic, the Weasleys have some actions that conflict with Harry and Hermione's values. For example, if the Weasleys were to make a deal with a dark wizard for the sake of their family's safety and Harry and Hermione found out. This could lead to a rift and hatred. Also, it could be related to a love triangle situation in a very convoluted way. Maybe one of the Weasleys unknowingly gets in the way of Harry and Hermione's relationship, or vice versa, which causes animosity.
In this fanfiction, perhaps Hermione uses her vast knowledge of magic. She might save the Weasleys from a dark wizard's attack. Maybe she discovers a powerful spell to counter a curse aimed at the Weasley family.
This fanfiction could be exploring the relationship between the Weasleys and Hermione in the context of the Harry Potter universe. It could involve things like Hermione spending time at the Weasley home, the Weasleys teaching Hermione something new about magic or wizarding traditions, or it could be a story that delves into how Hermione fits into the Weasley family's social circle.
It could be about the Weasley family's relationship with Hermione in the context of fan - created stories. Maybe it shows how they interact, support or have unique adventures together in the fanfiction world.
In the fanfiction, it could start with Hermione having a falling - out with her own family due to her magic. The Weasleys, seeing her distress, offer to adopt her. As a part of the Weasley family, Hermione would be involved in all their family traditions. She could bring her intelligence to help with family matters, like helping with George's business by using her logical thinking. And her relationship with Ginny would become even closer, like true sisters, sharing secrets and having girl - talk that they didn't have much opportunity for before.