Misunderstandings are also common. Maybe Percy is wrongly accused of something, and Annabeth believes the false rumors, causing her to hate him. Later, when the truth comes out, she realizes her mistake and starts to see his good qualities, which then turns into love. In some fanfics, it could be that Percy's actions are misinterpreted as being arrogant when in fact he's just trying to be confident in a difficult situation.
One possible reason could be competition. Annabeth is highly competitive and Percy's sudden appearance and his own skills might make her feel threatened, leading to hatred. For example, if he outperforms her in a training session or a quest task.
One possible reason could be a misunderstanding. Maybe Percy did something that Annabeth misinterpreted, like making a decision during a quest without consulting her first, which made her feel disrespected.
One possible reason could be jealousy. Maybe Percy gets more attention or recognition in their fictional world that makes Annabeth envious and thus appear to hate him.
One possible reason could be that the fanfiction misrepresents their characters. Maybe it portrays Percy in a way that Annabeth doesn't like or goes against the essence of their relationship as she sees it.
Maybe she's jealous of Percy's popularity at school. It could be that he always gets more attention, whether it's from teachers or other students.
A great fanfic in this category is 'Hate to Love'. Annabeth's hatred stems from her envy of Percy's natural talent at first. However, over time, Percy shows his vulnerability and his determination to protect his friends, including her. This makes Annabeth re - evaluate her feelings, and she gradually falls in love with him. It's a really interesting read that delves deep into their characters.
One possible reason could be jealousy. Maybe Rachel has something that Annabeth wants, like a closer relationship with a particular character. For example, if they both like the same guy, Annabeth might hate Rachel out of envy.
One possible reason could be differences in their divine natures. Percy is a son of Poseidon, a god associated with the sea and a more fluid, emotional element. Artemis is a virgin goddess of the hunt, very strict and unyielding in her ways. This contrast in their essences might lead to clashes and Percy's dislike.
It could also be due to some sort of magic or mind - control. A powerful enemy might have cast a spell on Annabeth, forcing her to turn against Percy. In this case, it's not really her own will but the result of external manipulation.
Well, one possible reason could be that Percy made a really stupid decision without consulting Annabeth first. Like, if he went off on a dangerous mission on his own when they were supposed to be a team. Annabeth is a very strategic person and she might feel betrayed or extremely frustrated by such actions.
It could also be that in the fanfiction, Percy is given a new power or ability that Annabeth sees as a threat. Or perhaps Percy is made to side with someone Annabeth dislikes, causing her to 'hate' him in that fan - created story. This shows how different plot elements in fanfiction can change the dynamics between characters.