My top dislikes in fan fiction.

#1) Ridiculous AU's. So you want to write a fan fiction, but want to place your own spin on the source material? A slight change to the characters personality's, or to the canon world is a great way to start on an interesting story. However, there are limits.

When you take a group of well known characters, and rewrite their personality's to the point where the only similarity between them and the canon character is there name, your taking things a bit to far. There is a reason these characters that we most commonly write about became popular in the first place, and that is that they were, regardless of faults, interesting. At the core of there personality, a character in fan fiction must still bear some similarity's to there canon counterpart, if they don't then you might as well just get rid of them and use your own OC.

The problem of ridiculous AU's becomes even worse, when, a writer takes his or her now non-canon compliment characters, and puts them in a world that has no connection to the canon world they originate in. The worst examples of this I have noticed, are the Naruto in high school stories, where an author has completely disregarded the entire plot of Naruto and thrown his characters, who only retain the barest of resemblance to the canon character, into a school, not in the Elemental Countries, but instead in America some where. When your fanfiction completely ignores both canon personality's of characters, and every aspect of the canon story, you are no longer writing fanfiction. You are writing a simple fiction without having been able to think of your own character names and descriptions.

#2) Poorly thought out crossovers. A crossover is a fantastic way to take a beloved character, and introduce them to new adventures, however, if you are writing a crossover, you need to make sure that the way the crossover between the two canons occurs makes sense. No matter what you use as an excuse, there is no way that the elemental nations of Naruto, somehow exist in the modern world of Bleach, with out anyone, anywhere, ever having noticed this huge land mass full of super powered people exists. It just doesn't make sense. Find a reasonable reason for your character to exist in a different world, the reason does not need to be complicated, or even original, as long as it works. Anything from spell/jutsu gone wrong, to accidental time travel, to immortality and the world changing around the character over hundreds or thousands of years. Any of these can work. What doesn't work is that Naruto took a walk one day, and somehow made it to fucking Hogwarts.

#3) Unreasonable pairings. The great thing about fanfiction, is that you, as a writer, are able to take two of your favorite characters, and place them in a relationship together. When you want a story that has Harry/Hermione, or Naruto/Sakura, or Ichigo/Rukia pairings, you can find it despite it not being canon compliant. However, some pairings, no matter how much you may want them, can never, and will never make sense.

The best example of the completely unreasonable pairing, is the ridiculous amount of Harry/Voldemort, Harry/Snape pairings. Firstly, I don't care how you write it, how you try and excuse it, there is no way any person with even a modicum of emotional health would ever enter into a relationship with a man who is both some fifty years older then them, and more importantly, killed his parents. Secondly, Snape was in love, or at least infatuated to with Lily, he was in many ways obsessed with her, to the point that even sixteen years after her death, he could not even think of loving another. There is no way he would simply cast aside all those feelings for Lily, and fall in love with her son, and if he did, it seems far more likely that he is simply trying to redirect his feelings to gain some measure of gratification. A rather unhealthy way of dealing with them.

#4) Ridiculous harems. I have no problem with a story having a harem pairing, however what I do have a problem with, is when a writer decides that the main character of there story needs to sleep with every single female character to ever appear or be mentioned in the source material. One main character with two, three or even four romantic partners can, when the story is well written be reasonable. As long as the writer allows for a good romantic buildup between the characters, it can work well, but when a writer decides that the main character should be able to be in a relationship with any female character, with build up that amounts to "Hi, I'm Blah Blah", "Hi Blah Blah, I'm Blah Blah, suck my dick." You're starting to get silly. So unless you are writing a harem story that is based primarily around lemons, please keep the harem size believable.

On a similar note, does anyone else think fanfiction.net needs to add a yaoi/yuri filter to the search options?