Just because it's written by fans doesn't mean other fans will be pleased. Get enough angry folks, and fanfics can fall under Broken Base
just like any other work.
- RainbowDoubleDash's Lunaverse has runs with the final story of the first season, 'At the Grand Galloping Gala.' One faction feels that the fic ruins things because it makes the Night Court too dark and evil, able to cause a whole town to suffer because one pony in it hates Trixie. One faction feels that the fic ruins things because it turns Trixie and co. into hypocritical criminals and Luna into a tyrant for letting them get away with what is essentially treason in order to expose/punish the (comparatively smaller) crimes of the bad nobles. A third group thinks that the fic breaks everything in both ways; that by implying that treason is the only way to fix the Court, it makes the Court far more broken and malign than before while also not actually solving the corruption (since Trixie and co. would get away with what they did). And a fourth faction is okay with the story or thinks the Night Court got off lightly.
- Double Rainboom was heavily hyped by fans prior to its release, but following its release has been met with heavily mixed reviews, mostly due to a large portion of the episode being a lengthy crossover with The Powerpuff Girls.
- The Conversion Bureau is pretty much the epitome of this. The original fic was pretty much pure Wish Fulfillment, with a few glaring, if unintentional, misanthropic themes. It was still mostly unremarkable. However, it attracted some of the crazier side of the fandom turning the premise into outright genocide, some saner folk who happened to like the premise, all pitted against the people who were horrified at the whole thing. Not helping was the tendency of some of the worse writers among the fandom to have huge amounts of Moral Dissonance, usually relating to The Right of a Superior Species, and some of the worse writers among the Anti-fans doing the same thing in reverse. The heat of the arguments nearly got both sides banned from FIMfiction, and they only got to stay when they agreed to settle down. Chatoyance's fics are prime targets of controversy. The way that Chatoyance handles criticism does nothing to mollify naysayers.
- Fans and haters of G4 alike seem to be split over the gory fanfiction "Cupcakes". Was it a bit of morbid (but ultimately harmless) fun, or was it the pioneer of the even worse fanon to come? Making the issue all the more hilarious is the fact that Cupcakes's author, Sgt. Sprinkles, has all but disowned the admitted Troll Fic.
- The divide over "Cheerilee's Garden" is even wider than the divide over "Cupcakes", many considering it either better than "Cupcakes" as in more entertaining, worse (most often worse as in even more disturbing), or on the same level of not having an impact on them (usually fans who like Grimdark and are seeking for something to get a reaction out of them).
- Courtney and the Violin of Despair's "woobie fic pretending to be a bash fic" premise sharply divided the author's fans. Some were content to trust the author to do a tasteful job, and did not feel disappointed after reading it. Others regarded the "bash fic" veneer as inherently unworthy, no matter how tastefully done, and refused to read it. This is part of the reason why the story has always lived in the shadow of the author's larger works.
- The whole genre of slash. Is it homophobic for (mostly straight female) writers to derail characters into OOC gay stereotypes for their own gratification? Is the previous criticism accurate, or is it groundless misogynistic hatred of a female-driven genre from people who don't even read it? Are people who avoid slash only doing so out of homophobia? Is it okay to warn for slash? The list goes on.
- Any time there is fanfiction of a work where fanfiction ban were stated by the author fanbase brakes between those who take it seriousy and those who write fanfiction.