With Sakura, it could be a complex situation. At first, she might be angry at Naruto for leaving, thinking he's being selfish. But as time passes, she might come to understand his reasons. This could potentially lead to a more empathetic relationship between them, as she realizes she may not have been as good a friend to him as she could have been while in Team 7.
Regarding Kakashi, there would be a strain. Kakashi might feel like he failed as a sensei. He might try to reach out to Naruto, but Naruto could be resistant. However, if Kakashi truly tries to understand Naruto's perspective, it could lead to a deeper and more meaningful relationship in the long run, as they both grow from the experience.
His relationship with Sasuke would be greatly affected. Initially, Sasuke might not care much as he's so focused on his own path. But later, he might realize that Naruto was an important part of the team dynamic. Without Naruto, Sasuke may find that he misses the competition and the unique bond they had, which could lead to some self - reflection for him.
If Naruto quits Team 7 in the fanfiction, it could introduce a whole new set of storylines. There could be a search for Naruto by Team 7, which would involve them exploring new places and meeting new characters. The emotional impact on the other characters would also be significant. Sakura might feel guilty, thinking she could have done something to prevent Naruto from leaving. Sasuke might be more conflicted about his own goals, as Naruto was always a driving force in his life. And Kakashi would have to deal with the failure of keeping the team together, which could lead to his own character development in unexpected ways.
One reason could be a sense of not being understood. Maybe Naruto feels like his teammates, Sasuke and Sakura, don't truly get him. Sasuke is often preoccupied with his own revenge, and Sakura has her eyes mainly on Sasuke. Naruto might feel left out and that his goals are not aligned with the team's, so he decides to quit.
The OC might have a romantic interest in one of the members of Team 7. For instance, if the OC likes Sasuke, it could create some jealousy among the other characters. This would definitely change the dynamics of the relationships within the team. On the other hand, if the OC is more like a mentor figure to Sakura, it could improve Sakura's self - confidence and her relationship with the rest of the team.
In fanfiction, Naruto joining Team 10 would create some interesting relationship changes. Naruto is a bit of a loner at first in the original story, but in Team 10, he could be the glue that holds them together. He has a way of making people feel important. For Ino, Naruto could be a source of inspiration in terms of becoming stronger. His presence would also add more competition among the team members, which could either strengthen or strain their relationships depending on how they handle it.
Perhaps Naruto quits Team 7 in the fanfiction because of a betrayal. He might find out that one of his teammates has been secretly working against him or has lied to him about something really important. This could shatter his trust in the team and make him want to leave. Or it could be due to an accumulation of small incidents. Like constantly being the one to get in trouble for the team's mistakes, or not having his opinions heard when it comes to team strategies. Over time, these little things can build up and make him feel that he's better off on his own.
It could also be due to a major disagreement with Kakashi. Maybe Naruto has a different vision for how they should operate as a team or a particular mission that goes against his values, causing him to leave.
If Naruto gets a new bloodline, his relationship with Sasuke could become even more complex. Sasuke might be jealous of Naruto's new power, or it could be a reason for them to team up again to explore the origin of the bloodline. With Sakura, she might see Naruto in a new light, either being more attracted to his new strength or being worried about the potential risks of the bloodline.
Well, Naruto would be like a catalyst for change in the team dynamics. He'd bring his unique sense of humor and determination. This would rub off on the others. He could help Obito see the value in the team more clearly. With Kakashi, he could show him that it's okay to rely on others. And for Minato, Naruto could be a source of pride and motivation. His presence would create a more family - like atmosphere within the team, which would make them fight even harder for each other.
One possible reason could be a sense of being undervalued. Maybe he felt that his teammates didn't fully appreciate his efforts during the Wave mission. For example, if Sasuke got most of the credit, Naruto might feel pushed aside.
The storyline would be completely different. Naruto's character development would take a new turn. He would no longer have the instant boost of power from the Nine - Tails. This might make him more vulnerable, but also force him to rely more on his own skills and training. His interactions with the other Jinchuuriki would also change. They might view him as a traitor to their kind or as a pioneer for a new way of living without the tailed beasts.