It could also be due to jealousy. If there was another character who seemed to be getting closer to Percy, Annabeth might lash out in a way that hurts his feelings. Like if a new demigod joined their group and Percy was being friendly, Annabeth might feel threatened and say something mean.
One possible reason could be miscommunication. Maybe Annabeth said something without realizing how it would come across to Percy. For example, if she was stressed about a quest and snapped at him when he was just trying to be helpful.
Another reason might be that Annabeth has her own insecurities. She might be afraid of losing Percy in some way, like if he was getting more powerful and she was worried he'd outgrow her. So she could push him away by hurting his feelings, not realizing it's a self - destructive behavior.
He could become withdrawn. Percy might start to distance himself from Annabeth, not wanting to be around her if she's going to be cruel. He might go off on his own and think about what she said, trying to figure out if he did something wrong.
Maybe in some fanfictions, Annabeth could be written as betraying Percy's trust. For example, she might side with his enemies or reveal his secrets, which would deeply wound Percy emotionally.
Love is a big reason. She loves Percy deeply and is afraid of losing him. In the world of the fanfiction, there could be many threats to their relationship, so she holds on tightly.
One possible reason could be her deep love for Percy. She might see his life as more valuable in the grand scheme of things, perhaps because of a prophecy or a mission that only he can complete. So, she chooses to sacrifice herself to ensure his survival.
Misunderstandings about their future plans often lead to fights. Percy might want to focus on one type of adventure while Annabeth has other ideas. They argue about it, but in the end, the love between them overcomes the differences and they kiss. This shows how their relationship is complex and full of different opinions that need to be resolved.
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.
Maybe it's a sign of closeness between them. In many relationships, sharing or wearing each other's clothes can show a deep bond. Annabeth might be cold and Percy's clothes are just there and convenient.
Maybe she's scared because the fanfiction portrays Percy in a way that's out of character for him. Like, it might show him being overly aggressive or having strange powers that she doesn't recognize, which makes her feel like she doesn't really know him anymore.
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.