Maybe the author just wants to add some humorous or unexpected elements to the story. In fanfiction, authors often take creative liberties and might portray Harry in this way to show his inexperience or awkwardness in romantic situations.
It can make him seem more human. Everyone has things they're not good at, and if Harry is a bad kisser, it shows that he's not perfect. This can make fans relate to him more.
Well, a bad Harry Potter fanfiction could be due to bad world - building. In the Harry Potter series, the world of Hogwarts and the wizarding world is so richly detailed. If a fanfiction fails to capture that essence or creates a really inconsistent world, it's bad. For instance, if the houses at Hogwarts suddenly have completely different characteristics that don't align with what J.K. Rowling created. Additionally, if the fanfiction has a really forced or contrived plot device just to get to a certain point, like a deus ex machina that solves all the problems out of nowhere, it's a sign of a bad fanfiction.
One characteristic of bad Harry Potter fanfiction is poor character development. Instead of staying true to the complex and well - developed characters in the original series, they might make them act out of character. For example, making Harry extremely cruel or Hermione overly ditzy. Another is a lack of consistency with the established magic system. In the original books, the magic has rules and limitations, but bad fanfiction might have magic solving every problem too easily or in ways that don't make sense. Also, bad grammar and spelling can be a big giveaway, as it makes the reading experience difficult and unprofessional.
It could be a new dark wizard or witch who has a vendetta against Harry. This person might have developed a new form of magic specifically to harm Harry, and the seizure is the first sign of this new threat.
It can divide the fandom. Some fans might be open to new interpretations like Harry as a 'bad boy' and enjoy the creativity, while others who are purists might be very much against it. This can lead to arguments and a split in the community.
A really bad Harry Potter fanfiction might be one where the author completely changes the personalities of the beloved characters. For instance, making Hermione mean - spirited when she's known for her kindness and intelligence in the original series. Bad grammar and spelling mistakes can also contribute to it being bad. Additionally, if the fanfiction tries to force a romantic relationship between characters that has no basis in the original story and does it in a cheesy or inappropriate way, it would be considered really bad.
I'm not sure specifically as there could be many different 'bad blood' themed Harry Potter fanfictions. It might be about a feud or bad relationship between certain characters in the Harry Potter universe, like perhaps a rift between two wizarding families or old grudges among Hogwarts students.
Among the popular bad guys in 'Harry Potter bad guy fanfiction' are the Dementors. Their terrifying nature and the mystery surrounding them make them a great subject for fanfiction. Writers can delve deeper into their origins and what makes them so evil. Another is Nagini, Voldemort's snake. Some fanfictions might give her more agency and intelligence, making her a more significant and menacing villain. And Severus Snape, while he was a complex character in the original series who turned out to be on the good side in the end, in some fanfictions he is rewritten as a true bad guy, exploring the 'what if' scenario of his character being completely evil from the start.