Well, it could be that the authors want to explore Snape in a different setting. Britain has so many ties to his past, especially his time at Hogwarts and his role in the war. By leaving Britain, fanfiction writers can show how he copes without those familiar surroundings. He can be a different person, or maybe find a new purpose in life. It also allows for new character interactions as he meets people outside of the British wizarding world.
Fanfictions often explore the 'what - if' scenarios. Snape leaving Britain is one such scenario. It might be because the writers think that Snape, who has been so deeply enmeshed in the British magical society, would have an interesting journey if he broke away. His departure could lead to exploring themes like isolation, redemption in a new place, and dealing with his past on his own terms, away from the prying eyes of those who knew him in Britain.
The fanfiction 'Snape's Exodus' is also worth checking out. Here, Snape's departure from Britain is a complex decision influenced by his past actions, his need for solitude, and his hope to outrun his reputation. It's a well - written piece that explores his character in a new context.
Some Dramione fanfictions involve Ron leaving Hermione to create a new narrative space. By removing Ron from the Hermione - Ron relationship, it allows for a different dynamic to develop between Hermione and Draco. It gives the author a chance to explore new storylines that might not be possible with the traditional Hermione - Ron relationship intact. Also, it can be a way to add drama and conflict, as Hermione has to deal with the aftermath of being left, and Draco can be introduced as a new element in her life during this vulnerable time.
Sometimes it's to create drama. His leaving shakes up the whole dynamic of the NCIS team, which makes for an interesting plot. There are relationships within the team that are affected, and new storylines can emerge from that.
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.
Some fanfictions might do this out of a desire for shock value. They want to create a controversial and extreme version of the character to get more attention.
Some fanfictions focus on 'Harry leaves Ron and Hermione' because it creates a lot of drama. The trio is so iconic in the original series that breaking them apart in a fan - created story can lead to all kinds of interesting plot developments. It also allows the author to explore the individual characters more deeply. Without Harry around, Ron and Hermione have to rely on their own strengths and face challenges alone, which can be a great character - building exercise. Another reason could be to introduce new relationships. Maybe Ron or Hermione forms a new alliance with another character in Harry's absence.
Some people write it to explore different storylines. Maybe they think Mcgee's character has reached a point where a change like leaving would add a new dimension to the overall NCIS story world.
Some people like it because it's a pairing that breaks the norm. In the original 'Harry Potter' series, their relationship is mainly that of a strict teacher and a student. Fanfictions allow for a different kind of exploration, a 'what - if' scenario where they could be more than that.
Some fans write 'Harry Trust Snape' fanfictions because they want to explore an alternative relationship between the two characters. In the original books, their relationship is mainly one of distrust. By writing these fanfictions, they can create scenarios where Harry sees Snape in a new light and trust develops.
Well, it's a unique take on the character. It gives a different visual aspect to Harry. Writers might use it to show a change in his personality or his journey. For example, long hair could symbolize a more carefree or wild side of him.