There could be emotional attachments holding the character back. Perhaps the character has a close friend or family member they don't want to leave. In the case of Peter and Tony, if Peter doesn't want to go, it might be because he feels safer with Tony around and is scared of being on his own without his guidance.
Another reason could be that the character has a premonition or a bad feeling about where they are supposed to go. In fanfiction, there can be all sorts of supernatural elements. So, the character might sense danger or some sort of negative energy at the destination and thus doesn't want to go.
Maybe the character is afraid of what lies ahead. It could be a new and unknown situation, like a dangerous mission or an unfamiliar place. For example, if it's a superhero fanfiction, the character might not be fully trained yet and is worried about getting hurt or failing.
It can introduce new plot elements. Maybe because Peter doesn't want to go, they discover a new threat or mystery right where they are. Or perhaps it causes them to seek help from other characters they wouldn't have otherwise, completely changing the direction of the fanfiction.
One reason could be that he has fallen in love with someone outside of Hogwarts and wants to stay with that person instead. He may feel that Hogwarts will keep him away from his beloved.
Perhaps he has seen a dark future for Hogwarts in a vision. He might think that by staying away, he can avoid that future or protect himself from some unknown danger. In fanfiction, there are often new and creative plotlines like this.
One possible reason could be to rescue a friend or ally who is in trouble there. Maybe someone he knew from his previous time in Afghanistan got caught up in a new conflict or was kidnapped by a local militia.
Some people might not go to a gay party because they simply have different interests. They may prefer other types of social gatherings, like a music concert or a sports event. Gay parties often have a unique culture that may not appeal to everyone. For example, the music and the style of dancing can be very different from what one is used to. Moreover, they may be worried about not fitting in as they might not be familiar with the specific gay sub - cultures and the unspoken rules within the party.
It could be part of a creative or fictional exploration of extreme intimacy in a relationship. But in reality, this is a very private and often inappropriate topic. It might be used in some fictional scenarios to show a high level of trust and lack of inhibitions between a couple. But we have to remember that these are just fictional ideas and real - life relationships are based on mutual respect, communication, and appropriate boundaries.
It could be that Peter was in a hurry and didn't have time to talk. He might have been in the middle of something important in his own life, like dealing with school or helping a friend, and just had to end the call abruptly.
One reason could be unqualified staff. If the doctors and nurses at the institute are not well - trained, it can lead to a lot of problems like wrong diagnoses and improper treatments.
One reason could be that he wants to experience a normal life. In the wizarding world, he is constantly in the spotlight as 'The Boy Who Lived'. At a Muggle school, he might be able to blend in and just be an ordinary kid for once.
One possible reason could be that in the fanfiction, his family might have decided to keep him away from the wizarding world for his safety. Maybe they feared the dark forces at Hogwarts, like Voldemort's followers.