What could be the reasons for Harry Potter to yell at Dumbledore in fanfiction?

One possible reason could be that Harry breaks school rules in the fanfiction. For example, if he ventures into the Forbidden Forest without permission. Dumbledore is strict about the safety of students and such disobedience might lead to punishment.

One possible reason could be a misunderstanding. Maybe Harry overheard something that made him think Dumbledore was planning something against him that he didn't understand. For example, if he heard Dumbledore discussing a dangerous mission for him without his full knowledge.

One possible reason could be that Mrs. Black has said or done something to endanger his friends. For example, if she reveals some secrets that put Ron and Hermione in danger, Harry might yell at her out of anger and protectiveness.

One reason could be a difference in ideology. Harry might have come to believe that Dumbledore's methods, like keeping secrets from him, are not in the best interest of the wizarding world. For example, Dumbledore withheld information about Harry's connection to Voldemort which put Harry in more danger at times. Harry could stand up to him to demand more transparency.

One reason could be a misunderstanding. Maybe Harry discovers some actions of Dumbledore that seem wrong at first glance, like the way he's been handling secrets about Harry's past or Hogwarts' safety. For example, Dumbledore's decision to keep Harry in the dark about certain prophecies might make Harry feel betrayed and lead to a conflict.

One reason could be secrecy. If Harry finds out that Dumbledore has been keeping major secrets from him all along, like about his family or his true role in the wizarding world, he might start to hate him. Another reason could be manipulation. If it seems that Dumbledore has been manipulating Harry's actions for his own gain, that would be a valid cause for hatred in fanfiction.

One possible reason could be a difference in ideology. Maybe Harry starts to question Dumbledore's decisions regarding the war against Voldemort. For example, Dumbledore's secrecy about certain things might make Harry feel left out and manipulated. Another reason could be personal pride. Harry has grown into a powerful wizard and may not want to be under Dumbledore's constant guidance and control any longer. He might think he can handle things on his own better. Also, it could be due to the influence of other characters. If some new friends or allies have different views on Dumbledore, they could sway Harry's opinion.

In some fanfics, it could be due to a conflict over a magical object or a spell. Suppose Lily finds a powerful magical item and wants to use it in a way that Harry thinks is dangerous. This difference in opinion might lead to Harry yelling at her to stop her from doing something reckless.

It could be that Harry finds out about Dumbledore's secrets regarding the Deathly Hallows. If Harry thinks Dumbledore was more interested in the Hallows for his own purposes rather than for the greater good, it might make him hate Dumbledore.

One possible reason could be that Harry has discovered something about himself or his past that he thinks Dumbledore might not approve of or might try to stop him from exploring further. For example, if he found out some dark magic connection in his family history that he wants to understand on his own without Dumbledore interfering.