One key moment could be when Naruto is training hard and Kakashi is secretly observing to make sure he doesn't overexert himself. Another might be during a dangerous mission where Kakashi keeps a close eye on Naruto to protect him from hidden enemies.
Kakashi may become more empathetic. By constantly watching over Naruto, he gets to understand Naruto's struggles better, which could make him more in tune with his own emotions and those of others.
He might be amused by the creative interpretations of the Naruto world. Fanfictions often take the original story in new and unexpected directions, and Kakashi, with his sharp mind, would likely find some of these ideas interesting.
At first, it might be awkward. Kakashi is used to being a mentor figure, and now he's in a position of being 'adopted'. But as time passes, Naruto's positive energy starts to rub off on Kakashi. Kakashi becomes more carefree and starts to enjoy life more, like Naruto does.
Well, there could be. Fanfiction writers love to explore unique and unexpected relationships. Since Naruto and Kakashi are both popular characters in the Naruto universe, some writers might come up with such a plot for the sake of creativity and exploring different storylines. But it's not a part of the official Naruto story.
Sasuke could be a popular character. He might be involved in the story in a way that either helps or hinders the situation where Naruto hurts Kakashi. For example, if Sasuke tries to stop Naruto from doing something stupid that would hurt Kakashi.
Another reason could be related to Kakashi's past actions. If there are some secrets or things Kakashi did in the past that come to light and Naruto doesn't like them, he could snap at Kakashi. Naruto has a strong sense of justice and loyalty, so if he feels betrayed or misled by Kakashi, his reaction could be to snap.
Kakashi might be initially surprised. But then, he would probably use it as a teaching moment for Naruto. He could say something like 'Naruto, stealing is not the way of a ninja.' And then give him a punishment like extra training.
One possible reason could be that Kakashi is preoccupied with other important matters in the village. Maybe he has some top - secret missions or tasks assigned by the Hokage that demand his full attention, leaving him with little time to focus on Naruto.