McGonagall might notice Harry's distrust and feel hurt or frustrated. She may try to figure out what went wrong but find it difficult as Harry is not forthcoming. Their interactions become less warm and more formal. For example, in class, Harry may be less likely to ask for help from McGonagall, and McGonagall may be more strict with Harry as she doesn't understand his change in attitude.
On the other hand, it could bring Harry closer to some characters who also have doubts about McGonagall in the fanfiction. They might form a sort of alliance based on their shared suspicion, which could lead to new storylines and developments in the fanfiction.
His friends might be divided in their opinions. Some of them might still trust Dumbledore wholeheartedly and think Harry is overreacting. This could lead to arguments and a strain in their relationships.
It could also be due to some actions of McGonagall that seemed suspicious to Harry. Perhaps she made a decision regarding Hogwarts or Harry's safety that Harry didn't fully understand at the time. In the complex world of the wizarding school, decisions are often made with many factors in mind, but Harry might not be aware of all of them, leading to his distrust.
The dynamic becomes very strained. Harry's lack of trust in Ron means that their usual banter and easy camaraderie is gone. Hermione will be stressed because she values both of their friendships. She may end up spending more time with Harry to try to help him through his doubts, which could make Ron jealous. Ron, on the other hand, might become defensive and start acting out, which only makes Harry trust him less. This could lead to a cycle of misunderstandings and a breakdown of their friendship triangle.
Well, it could show that Harry gravitates towards the younger characters because they are more innocent and less likely to have ulterior motives like the adults. He may start to build a sort of 'youth alliance' in the fanfiction. They would support each other and rely on one another more than on the adults. Harry could be teaching them magic in a different way, a way that is not influenced by the adults' traditional methods, which he may distrust.
Well, it might make Harry more isolated. In the original story, Dumbledore was like a guiding figure for Harry. If Harry doesn't trust him in the fanfic, he may not trust the advice Dumbledore gives about other characters either. So he might be more cautious around people Dumbledore was friendly with, like Hagrid. He might think they are also in on Dumbledore's secrets and not be as open with them.
They could work together on a difficult task. By collaborating and seeing each other's skills and good intentions in action, Harry can regain his trust in Hermione. For instance, if they are in a dangerous situation and Hermione comes up with a clever plan that saves them both.
It could also be that in the fanfiction, McGonagall has shown some form of bias. Maybe she seems to favor certain students or groups over others, and Harry, being the one who always stands up for fairness, starts to distrust her when he notices this behavior. He might feel that she is not as just as he once thought her to be.
It completely flips their relationship. In the original story, McGonagall is a respected figure for Harry. But in this fanfiction, the hatred makes their interactions tense and negative.
It could become closer. Without Ron as a third party, Harry and Hermione might rely more on each other. They would have more one - on - one study sessions and adventures, which could strengthen their bond.