It could be that Ron's actions were causing problems within the Order of the Phoenix. If Ron was being stubborn and not following the plans or orders set by the Order, which Sirius is a part of, Sirius might get angry. He would be frustrated with Ron for not being a team player and potentially endangering the mission and the lives of others.
Well, it might start with Sirius yelling at Ron and Ron feeling really bad about it. Then, Ron might try to make amends by doing something brave or helpful. For example, he could volunteer for a dangerous mission to prove his worth and show Sirius that he can be trusted.
One reason could be to create drama. Fanfiction writers often like to add a lot of angst and turmoil to the story. By having Ron cheat on Hermione, it can create a huge rift not only between them but also among their friends. Another reason might be to explore different character traits. Maybe showing a darker side of Ron that wasn't explored much in the original books.
Ron could be mad because he has some unspoken feelings for Hermione that he's not fully aware of yet. When he sees her at Quidditch, enjoying herself without him, it stirs up these confusing emotions inside him. Additionally, if there were rumors going around Hogwarts about Hermione and someone at Quidditch, Ron, being the hot - headed person he can be, might get angry without even verifying the rumors.
One idea could be that Ron has been having a bad day and seeing Hermione at the Quidditch match makes him snap because he feels she should be studying instead. Maybe he's worried about upcoming exams and thinks Hermione is being too carefree. Another idea is that Ron is jealous. He sees Hermione chatting with one of the Quidditch players and gets mad because he secretly has feelings for her but doesn't know how to express it.
Another possibility is a jealous rival. Maybe there's someone who is jealous of Gohan's power or his relationship with certain characters. This rival could do things to annoy Gohan and push him to the edge of his temper.
It could be Vegeta. Maybe Vegeta does something really underhanded like stealing Goku's senzu beans or trying to take all the credit for a victory that Goku also contributed to. Goku, being a fair - minded person, would get angry at such behavior.
Perhaps in the fanfiction, Sirius is mad at Harry because Harry has befriended someone Sirius doesn't trust. Sirius, being protective of Harry, might see this new friendship as a threat. He could be worried that this person will lead Harry astray or put him in danger, and his anger towards Harry stems from his concern for Harry's well - being.
He could become more isolated. After being punched, his friends might avoid him for a while. For example, if Harry punches him, Harry might need some time to cool off and not want to be around Ron. This would make Ron feel really lonely and regret his actions that led to the betrayal.
There could be. Fanfiction is a vast and diverse world where authors can take the characters in all kinds of directions. But it's important to note that this isn't in line with the general perception of the characters' relationships in the official books. It might be an interesting exploration for some who like to see how different twists can change the story, but others might be put off by it.
One reason could be ChiChi's overbearing nature. She is often very strict about Goku's training and how he spends his time. In fanfiction, this could be exaggerated to the point where Goku finally gets fed up. For example, if she constantly nags him about not doing enough chores around the house instead of training, it might push Goku to his limit.