It could also potentially lead to a more romantic development. In some fanfictions, a seemingly negative action like this could be a way for Percy to get Annabeth's attention in a different way. It might be a start of a new chapter in their relationship where they have to work through this incident and in the process, grow closer to each other.
Another consequence might be that it starts a comical chain of events. Maybe the apple misses Annabeth and hits someone else instead, like Grover, and then there's a whole lot of chaos and laughter that follows. The fanfiction could then take on a light - hearted, humorous tone from there.
One possible consequence is that Annabeth will be heartbroken. She's deeply in love with Percy, so his rejection would be a huge blow to her emotionally.
One possible consequence could be the breakdown of trust between Annabeth and Percy. Percy might feel extremely hurt and betrayed, which could lead to him distancing himself from her. Their friendship, which was the foundation of their relationship, might be severely damaged.
Well, one consequence could be that other students might see them and start gossiping. This could either make them the talk of the school in a positive way, like a cute couple everyone adores, or in a negative way if there are some who don't like them together. Another possibility is that their friends might react differently. Some friends might be really happy for them, while others might be a bit shocked or jealous. And it could also affect their own relationship. Maybe they become closer because of this public display of affection, or maybe they start having some insecurities about how fast things are moving.
One possible consequence could be Percy feeling betrayed and heartbroken. His trust in Annabeth would be shattered, and he might become withdrawn or angry.
Luke might become more enraged. Since Percy has thwarted his plan to do something to Annabeth, he could seek revenge. He might start plotting more devious schemes against Percy and Annabeth, or even their friends.
He could be frustrated with her. Maybe they had an argument earlier, and Percy, not knowing how else to express his feelings, throws the apple as a way of getting a reaction from her. It's like a childish way of saying 'I'm mad at you' without using words.
One consequence could be that she misses out on some creative interpretations of their relationship. Some fanfiction might actually have really interesting takes on their bond that could enhance her understanding in a different way. But on the other hand, by avoiding it, she maintains her own view of their relationship without outside interference.
Percy would likely feel a great sense of hurt and confusion. He might question his own judgment in trusting Annabeth. He could become more withdrawn and less trusting of others in general.
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.