Well, in the original story, the Dursleys are really mean to Harry. So, fans want to explore more about Harry's feelings towards them. It gives an opportunity to write about his pent - up anger and frustration.
The Dursleys represent the 'muggle' world that is so unkind to Harry at the start. Fanfiction writers like to expand on this dynamic. They show how Harry could have reacted differently if he wasn't so restricted by his situation. For example, in some fanfictions, Harry shows his magical abilities to the Dursleys earlier to shock them into treating him better. This explores the idea of power and how it could have been used in that relationship.
Because many fans feel that Harry was mistreated by the Dursleys in the original story. So they create fanfictions where he is taken away from that bad situation. It gives Harry a chance at a different and hopefully better life.
Many 'Snape Saves Harry' fanfictions exist because the relationship between Snape and Harry is so complex and full of potential in the original 'Harry Potter' series. Snape is a very ambiguous character, and his saving of Harry in the main story is a major plot point that fans love to explore further. They want to see different scenarios and motives for his actions.
They are popular because the Dursleys are such complex and disliked characters in the original series. Fanfictions give readers a chance to explore their motives and potentially redeem them. For example, we can understand why they treated Harry so badly in some fanfictions which might be due to their fear of the unknown world of magic.
One popular 'Harry Hates the Dursleys' fanfiction could be 'The Dursley's Worst Nightmare'. In this fic, Harry finally stands up to the Dursleys in a very assertive way. He uses his magic not to harm them but to make them understand how much they've wronged him.
The appeal lies in the fact that it gives a sense of empowerment. In the original series, bullying is there but not always fully addressed. In these fanfictions, Harry takes a firm stand. It also appeals because it can bring different characters together. Maybe Harry teams up with Neville, who was often bullied, to fight back. This creates new relationships and story arcs that fans love to explore.
Some exist because fans like to explore different power dynamics in relationships. They want to see how Harry, as a central and powerful character, can influence Ginny's actions and decisions.
Some authors write these fanfictions to show different sides of the characters. For example, Snape's action of hitting Harry could be a result of his own inner turmoil, perhaps related to his loyalty to Dumbledore and his hatred for James Potter. By writing about this, they can show Snape in a new light. Also, it can show Harry's growth in dealing with such a difficult situation. He can either become bitter or try to understand Snape's motives, which are interesting character development arcs.
Well, it could be to show different relationship dynamics. In the original story, they are very close friends. By having Harry leave Hermione, it can show how their friendship can be strained and how they might react to such a big change. It can also lead to new plotlines like Hermione having to form new alliances or Harry finding new friends in different places.
Maybe some people just want to explore a different and darker side of their relationship. In fanfiction, creators often take liberties to show complex emotions that might not be as obvious in the original books. Harry hating Ron could be a way to create drama and new storylines.
Some fanfictions like 'Harry Potter hides as a girl' exist because it's an interesting 'what - if' scenario. It allows authors to explore different aspects of the Harry Potter universe in a new light. They can play with the character dynamics and how the story would change if Harry had this different identity.