One possible reason could be jealousy. Maybe Ginny is jealous of Hermione's close friendship with Harry or her academic achievements. In the wizarding world, relationships can be complex, and Ginny might feel overshadowed by Hermione at times.
It could also be due to a misunderstanding. Perhaps Hermione made a decision that Ginny thought was wrong or unfair, without fully understanding Hermione's motives. For example, if Hermione influenced a Hogwarts policy that affected Ginny's Quidditch team.
Another reason might be related to Ron. Ginny could be angry at Hermione for something that happened between Ron and Hermione, like an argument or a situation where Hermione hurt Ron's feelings. Since Ginny is Ron's sister, she might feel the need to defend him.
In a fanfiction, it could be that Ginny is being too reckless. Hermione, being the more cautious one, is always worried about getting into trouble. If Ginny is constantly sneaking out or getting involved in dangerous adventures, Hermione might yell at her to stop putting herself and others at risk.
On the other hand, it could also be a turning point for the better. If they talk about what led to the yelling, they might clear up misunderstandings and become closer. For example, if Ginny was yelling out of fear for Hermione's safety in a dangerous situation, Hermione might realize Ginny cares deeply for her.
It could strain their friendship. Yelling is not a positive form of communication, and it might make Ginny feel attacked. She could become defensive and start avoiding Hermione. On the other hand, if Ginny understands Hermione's reasons, it could lead to a deeper conversation and actually strengthen their bond. For example, if Hermione yells because she's worried about Ginny's safety, Ginny might realize how much Hermione cares.
It could also be related to a boy. If both Ginny and Hermione are interested in the same guy, say Harry Potter, Hermione might stand up to Ginny to assert her own feelings or to clarify some misunderstandings that Ginny has about her relationship with the boy. This can create a tense situation between them in the fanfiction.
Maybe she's yelling at Ron. Their relationship in fanfictions can be quite complex. If Ron says something insensitive or does something stupid, like forgetting an important task that could put their mission in jeopardy, Hermione would surely yell at him.
One possible reason could be Snape's unfair treatment of Gryffindor students in the fanfiction. Hermione, being a strong advocate for justice and fairness, might not be able to tolerate his constant bias against her house. For example, if Snape gives Gryffindor students harsher punishments than students from other houses for the same infractions, Hermione would likely be furious and yell at him.
Hermione might run away crying. This would be a common reaction as she is a sensitive person. She could then go to Harry for support, and they might come up with a plan to resolve the issue with Molly.
One possible reason could be that Mrs Black's old - fashioned pure - blood views conflict with Hermione's more inclusive and progressive ideas. Hermione, being a Muggle - born witch, might not tolerate Mrs Black's snobbish and discriminatory remarks about non - pure - blood wizards and witches.
Perhaps Snape was being overly harsh with one of Hermione's friends. She is very protective of Harry and Ron. If Snape said something mean or did something to harm them, Hermione would surely stand up and yell at him. For example, if he gave Ron a particularly difficult detention for no real fault of his own.
In a fanfiction, Ginny could be out to get Hermione because of a prophecy or some sort of ancient magic that pits them against each other. Maybe there's a hidden aspect of their characters' destinies that was never revealed in the original series. For example, a prophecy that only one of them can fulfill a great task at Hogwarts, and Ginny, believing it should be her, decides to undermine Hermione.