Well, in such fanfiction, Harry's neglect by his parents can cause him to have a deep - seated fear of abandonment in his friendships. This could lead to him constantly testing his friends' loyalty. On the other hand, his friends, if they are true friends, will be more patient with him and try to show him unconditional love, which in turn can strengthen their relationships in the long run.
His relationships with his peers can become more intense. For example, with Iruka - sensei, Naruto might cling to him more as a father figure. With his teammates, he may be overly eager to prove himself worthy of their friendship. He could be more sensitive to any signs of rejection from them.
It might make his friends a bit wary at first. Since this is an unusual and powerful thing to happen, they could be concerned about how it's changing Harry. But as they see that Harry is still the same person deep down, they would gradually accept it.
It could make him very distrustful at first. He might have a hard time believing that others truly care about him. For instance, when his friends try to be nice, he might think they have ulterior motives.
His relationship with Ginny could also be affected. Ginny is a passionate Quidditch player herself. She might initially be sad that Harry is leaving the sport. But if she truly loves Harry, she will come to understand his reasons and support him. And Harry might feel guilty for disappointing Ginny, which could add some tension to their relationship at first.
His friends might be initially terrified. Hermione, for example, would be both scared and immediately start researching how to reverse it. Ron would probably be more shocked and not know how to react at first. Their friendship would be tested as they try to figure out what to do. They might have to keep Harry's transformation a secret from other students to protect him from being hunted or experimented on.
Well, it could make his relationships more volatile. His friends might be taken aback by sudden outbursts similar to Lily's. They may need time to adjust and understand that it's not really Harry being mean, but rather this new aspect of his personality. For example, Ron might initially be confused and a bit hurt, but as he realizes it's part of this new 'Lily - like' Harry, he could learn to handle it better and be more patient.
Well, it would be a huge blow to his friendships. Naruto's friends are drawn to his big heart and strong emotions. An emotionless Naruto would not respond in the same warm way. He might not share in their joys or sorrows. Sakura, for instance, would miss his determination and the way he used to encourage her. His friends would have to work hard to reach out to him, but they may also start to drift apart because the emotional connection is no longer there.
Well, his friends would likely be very confused and hurt. They know Naruto as a determined and kind - hearted person. If he's brainwashed, they might initially try to reach out to him, thinking it's just a temporary state. But as time goes on, they could become distrustful if he starts to act against them. Sasuke, for example, might be even more conflicted, seeing Naruto in such a different state. And Sakura would be heartbroken, as Naruto has always been a source of hope and friendship for her.
If Harry changes his look to seem more intimidating, it might make some of his enemies more cautious around him. For example, if he has a more severe look with a long beard and a scowl, the Death Eaters might think twice before attacking him. As for his friends, they might be a bit taken aback at first but would quickly accept the new look.
With Shikamaru, Naruto's early Rasengan might make Shikamaru more interested in teaming up with him. Shikamaru is smart and he would recognize the potential of having Naruto with his powerful jutsu on their side for missions. So they could form a stronger bond based on mutual respect for each other's abilities.