One example could be a fanfiction where Naruto gets into an argument with Sasuke, who he considered a friend, due to a misunderstanding about Sasuke's actions towards the village. In this fic, Naruto might lash out verbally at Sasuke, expressing his disappointment and anger. Another could be a situation where Naruto has a falling out with Sakura over her continuous pursuit of Sasuke in a way that endangers the team. He might 'bash' her for not thinking about the bigger picture and only focusing on her personal feelings for Sasuke.
Some people write it for the drama. It adds a new and different perspective to the Naruto story. By having Naruto 'bash' his friends, it creates conflict, which is interesting to read.
There's a fanfiction where Naruto constantly challenges Sakura's abilities and worth. It shows Naruto being frustrated with Sakura's lack of growth in certain aspects. But these types of fanfictions can be a bit controversial as they go against the more balanced view of Sakura in the official story. They might also be written from a perspective of a Naruto fan who didn't like how Sakura was portrayed in relation to Naruto in the original work.
Another reason could be that some fans are so strongly attached to Naruto that they view any character who they think treats Naruto poorly as a target for criticism in fanfiction. Sakura, at times, did seem to take Naruto for granted in the original story. So, these fans write fanfictions to express their dissatisfaction with her character. Also, it could be a creative outlet for those who want to explore a different dynamic between Naruto and Sakura, one where Naruto is more assertive against her perceived flaws.
In a fanfiction where Naruto and Madara are friends, it could completely change the Naruto storyline. Their friendship might start from a mutual understanding of their strong wills. Naruto, with his belief in redemption, could see past Madara's actions. And Madara, who has been alone for so long, might be drawn to Naruto's positive energy.
One way for Naruto and Ibiki to be friends in a fanfiction could be through a shared love for the village. Ibiki, who has dedicated his life to protecting Konoha, sees Naruto's potential to be a great protector. Naruto, in turn, admires Ibiki's loyalty. They often meet in secret to exchange stories about their ninja lives, and over time, this connection deepens into a strong friendship.
You could start by sharing your enthusiasm for the fanfiction and explaining why you think it's so great. Maybe talk about the unique storylines or interesting character developments.
One way could be to have the characters share common interests or goals related to the Naruto universe. This can naturally bring them together and start a friendship.
In Naruto fanfiction, making friends might involve characters discovering mutual respect for each other's skills or qualities. Maybe they team up for a mission and realize they work well together and enjoy the partnership, which turns into friendship.