One reason could be betrayal. If someone he trusted, like a fellow ninja or an old acquaintance, turned out to be working for his enemies, that would surely make him pissed. It's a huge blow to his trust, which is a big part of his character.
Sasuke could be a possible cause. If Sasuke were to go back on his word about protecting the village or if he were to harm their friends again, Naruto would be pissed. Their relationship is complex, and Sasuke's actions often have a strong impact on Naruto.
Sasuke could make Naruto pissed off if he goes back to his old ways of seeking power and revenge. Naruto has worked hard to bring Sasuke back to the right path, and if Sasuke strays again, it would surely anger Naruto.
A new, powerful and arrogant villain introduced in the fanfic could be the cause. This villain could constantly mock Naruto and his ideals, and try to undermine his efforts to protect the village. Such blatant disrespect would make Naruto really pissed off as he is very protective of his home and the values he stands for.
Sasuke could be the cause. If Sasuke were to betray Naruto again in the fanfiction, it would surely make Naruto pissed off. Their relationship is complex and Sasuke's actions have a big impact on Naruto.
No, these are not common. People usually try to maintain their dignity and privacy, and such situations are not things that are regularly talked about in general society. It involves personal privacy and bodily functions which are not topics for normal public conversation.
I really like 'Doflamingo's Unseen Side'. It presents a different perspective on Doflamingo. It has a lot of action scenes and also explores his relationships with other characters in the One Piece universe in a unique way.
For Doflamingo, you can focus on his flamboyant and unpredictable nature. Show his sadistic side in how he deals with enemies, but also explore his more vulnerable moments, like when his plans are thwarted. For Crocodile, emphasize his cool and calculating demeanor. Let his past failures fuel his actions in the fanfiction, like his determination to regain his lost status. Maybe show how Doflamingo's chaos sometimes clashes with Crocodile's order.
One character that would make for an interesting pairing with Doflamingo in a crossover fanfiction is Zoro. Zoro's strong sense of justice and his skills as a swordsman would clash with Doflamingo's devious ways. They could have epic sword battles, and Zoro might be the one to cut through Doflamingo's strings, both literally and metaphorically. Also, Nami could be paired with Doflamingo. Nami's intelligence and ability to manipulate situations for her own gain, although in a more positive way compared to Doflamingo, could lead to some really interesting interactions. She could try to outwit him in a game of wits.
The title 'peter parjer is pissed fanfiction' gives us some clues. 'Peter Parjer' is the name of someone, perhaps a character from a book, movie, or game that the fanfiction is based on. 'Is pissed' is an informal way of saying he's angry. Fanfiction can cover a wide range of genres and themes. So this could be an action - packed story where Peter's anger leads him into battles, or it could be a more emotional piece where he's pissed at a loved one and has to deal with the fallout. It could also be a comical take on his anger, with humorous situations arising from his pissed - off state.