Cell - like characters are often antagonists. Since Cell was such a major foe in the original series, new versions of Cell - like beings could be created in fanfiction to make Gohan angry. They might target his loved ones or the Earth itself, provoking Gohan's rage.
Another scenario might be when someone undermines his power or mocks his Saiyan heritage. Gohan, having grown up with a sense of pride in his Saiyan roots, would get angry and show his true strength to prove them wrong. He might also get angry if he sees innocent people being bullied or oppressed, as he has a strong sense of justice.
One possible reason could be that Videl does something that endangers herself. Gohan, being protective, might get angry out of fear for her safety. For example, if she recklessly jumps into a fight without proper training or preparation.
However, it could also be a turning point. If Gohan realizes that his anger is misdirected or if he communicates his reasons for being angry to Videl, it could strengthen their relationship. They could learn more about each other's boundaries and grow closer as a result.
It could be due to unfair treatment from teachers. For example, if he's blamed for something he didn't do just because he's a Saiyan or has special powers. Teachers might be prejudiced against him, which would lead to his anger. He's a good - hearted person but constantly being misjudged would surely get on his nerves.
Well, maybe Gohan gets angry because Hercule takes all the credit for saving the world when in fact Gohan did a lot of the real work. In fanfiction, the writer might play up this injustice, making Gohan seethe with anger at Hercule's false bravado.
I'm not sure specifically as I haven't read this particular fanfic. But generally, it might be about the relationship and adventures of Gohan and Pan in a fictional and perhaps creative or alternative storyline created by the fanfic writer.
One good 'Pan x Gohan' fanfic could be 'The Family Bond'. It focuses on their relationship in a post - Saiyan - threat world. It shows how Pan looks up to Gohan in a very sweet way.
Well, clearly Gohan and Baby Pan are the main characters. Gohan, being an experienced fighter and Son Goku's son, brings his strength and knowledge. Baby Pan, on the other hand, is full of potential and innocence, which makes her an interesting character to explore in the fanfiction.
It could be a new, unknown enemy. Maybe someone from a far - off planet who has a grudge against the Saiyans. This character could be really powerful and sees Gohan as an easy target at first, so he throws a punch.