Mrs Black could be so offended that she starts to plot against Hermione. For example, she might try to get Hermione into trouble with the Hogwarts authorities by spreading false rumors about her.
On the other hand, Hermione's actions might earn her respect from some of the students who also oppose Mrs Black's archaic ways. They might see Hermione as a hero for standing up to such a difficult and unpleasant character.
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.
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.
Harry might become more determined to prove Snape wrong. He's a stubborn character, and Snape's yelling could fuel his desire to show that he's not the misbehaving student Snape seems to think he is.
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.
It might become more strained. Mrs. Black could be offended by Harry's outburst and hold a grudge, making future interactions difficult.
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.
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.
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.
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.
One possible reason could be that Harry did something reckless without consulting Hermione. For example, if he went off on his own to face a dark wizard, Hermione, being the cautious and logical one, would be furious. She values planning and teamwork, and Harry's solo actions might seem to her as endangering himself and others needlessly.