What are the common reasons for Snape being depicted as a traitor in fanfiction?

Well, in certain fanfiction, Snape can be seen as a traitor. But we have to consider the context. These stories might explore different aspects of his character, like his loyalty to different sides or his hidden motives. It's not always a straightforward 'yes' or 'no' when it comes to Snape being a traitor in fanfiction.

One reason could be his quirk. His electric quirk might make him a target for villains to manipulate. They could use his power for their own evil plans.

One possible reason is Snape's prejudice. He might have some sort of bias against Gryffindors in general, and Hermione, being a very Gryffindor - like student, gets the brunt of it. He may expect her to make mistakes typical of Gryffindors like being overly bold without thinking. Another factor could be that Hermione is so intelligent and inquisitive that Snape feels threatened. He likes to be in control of the knowledge in his classroom, and Hermione's constant questions and thirst for knowledge might make him act tough towards her.

In fanfiction, the author might want to explore Snape's past more deeply. Maybe there are events in his life that could have made him truly side with Voldemort. For example, if he had been more influenced by the dark arts from a younger age or had different relationships with other dark wizards that pushed him towards Voldemort. Also, it could be a way to show how different choices could have changed the whole 'Harry Potter' story.

A creative reason could be a magical prank gone too far. The Marauders or some other mischievous students play a prank on Snape using a new, untested spell. The spell backfires and Snape ends up in a state where he needs to be diapered. This would lead to a story of revenge, forgiveness, or just chaos at Hogwarts.

One reason could be to add a new twist to the story. Fanfic authors might want to make the familiar character of Dumbledore more unpredictable. Another reason might be to explore the idea of power corrupting. Since Dumbledore had a great deal of power, showing him as insane could be a way to show how that power might have affected his mind over time.

Another reason might be that Harry is suspected of sneaking around in areas where he's not supposed to be. Snape, as a vigilant teacher, may punish Harry to maintain discipline in the school. He may think Harry is up to something related to the ongoing dangerous situations in the wizarding world and wants to keep him in line.

One reason could be for a darker and more edgy take on the story. Writers might want to explore how Naruto would be if he faced extreme hardships that pushed him to the brink of mental instability.

A common reason is that he's under extreme stress. In the world of Hogwarts, Snape has to constantly balance his double - agent life. The stress of hiding his true allegiances from Voldemort and the Order of the Phoenix can take a toll on his body. So, it's not unthinkable that this stress could make him physically ill, leading to vomiting. Another reason could be his love for Lily. In some fanfictions, memories of her, especially painful ones like her death, can be so overwhelming that it causes a physical reaction like throwing up.

One common reason could be his love for Lily. Since Harry is Lily's son, Snape might feel an obligation to protect him out of his undying love for her. It's like he's trying to preserve a part of Lily that still exists in the world through Harry.