These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Broken Base: One of the site's main problems is its failure to reconcile the pieces—the different species hate each other, the more normal fetishists hate the weirder ones, the furries who don't like furry porn hate all the fetishists, and everyone hates the diaperfurs. Fortunately, they only snipe at each other in the forums, and search filters make it easy to apply legit uses of the Don't Like, Don't Read.
This submission by fursuiter Dogbomb, which spread through FA's userbase like wildfire after just a couple of weeks; Dragoneer called it "The Greatest Thing You'll Read on FA. EVER."
Fan Dumb: Lots of things trigger this. Like a particular species? You're hated for it. The new banner of the month has been posted? They Changed It, Now It Sucks. Someone drew Rule 34 of a beloved character? They're dirty pigs that should burn!
The trope was taken to the extreme when there was a firestorm of journals from many people talking about how one artist quit after Dragoneer supposedly did nothing to stop another person from stalking and harassing her. This caused many people who only heard the gist of the story to suddenly make announcements that they are leaving Fur Affinity and are going towards Weasyl, another furry art site. Naturally, the the firestorm grew out of control once people started to say things like how Dragoneer did nothing to an alleged pedophile or how he only cares about people who suck up to him.
Fan Haters: Encyclopedia Dramatica, who pretty much loved picking on them, and the members of deviantART who find the site odd.
Saying you like Oblivion, Sonic, anything by Apple, or from Japan on the forums will typically result in someone expressing their desire to kick you in the face. (This is especially bad around the gaming forum, in which nearly every thread gets derailed into Blind Bashing and Fan hatred)
The fan base also has tendencies to display traits from the Mad Bride/Groom and the Mad Matchmaker. If someone on the site gets popular enough with their art and have their characters with fleshed out histories, expect at least a few people to either openly whine that the character is not in their tastes (fetishes, sexual orientation, etc.) or how they know the character better than anyone else.
There are also people who blast others for liking certain fetishes that they don't likfe.
Fetish Fuel/Fetish Retardant/Nightmare Fuel: Most forms of fetish-based art center around these. One person's ticket to having a nightmare and/or puking in the trash can is another person's ticket to getting it up.
Hate Dumb: Quite a bit of this directed towards the site, but examples are also found on the forums and in people's journals.
Mary Sue: Whether or not it actually counts, since a lot of the "Mary Sue" examples are either lampshaded or all-out parodies.
Hilarious in Hindsight: When InkBunny (an artdump site similar to FA) was launched in 2010, many people — some of whom probably never even went to the site — instantly hated it because it was openly accepting of cub porn, which gave it the image of being a "cub porn site" (the nickname "Pedobunny" was coined soon after the site's launch). Before Thanksgiving that year, Dragoneer announced that all forms of cub porn would be banned from FA as a result of numerous issues (mainly the cancellation of their account with AlertPay) coming to a head. After the ban started being enforced, dozens of artists — mainly those who draw cub porn — said "Screw This, I'm Outta Here" and migrated to InkBunny, causing the amount of cub porn to significantly increase...
Internet Backdraft: Hoo boy. This was the result when the site banned cub porn in 2010. Despite the administrator explaining that the site would be in trouble without ad money due to advertisers threatening to pull away from the site because of cub porn (which they didn't want to be associated with due to policies and some laws), many people accused the site of buckling to the will of the advertisers and many pulled a Rage Quit over the site because of this issue.
The banner during Thanksgiving one year was changed to the site's mascots being extremely fat from stuffing themselves with food. While the change was just for a single day, nearly everyone exploded in fury over how disgusting the image was. This was then poked fun at in 2011 during the first week of August where the banner was changed to celebrate "Fat Bunny Week" and having the banner display the mascots turned into small and fat bunnies and the background has silhouettes of other furs screaming "THIS IS AN OUTRAGE!!"
Dear lord, My Little Pony week. Due to how popular and well-loved the show's second season became, the admins decided to celebrate by dedicating an entire week to the series. The second users saw the new MLP banner, ranting journals were created, art bashing MLP was made, and some users even left the site—or threatened to leave, which they probably didn't. Imagine all the hate the show already receives for all the wrong reasons, but with furries. And to make things worse, some artists added fuel to the fire by drawing nothing but MLP art in hopes to piss off all the haters. The admins were so fed up with the complaints and pointless arguing that they ended MLP week after three days, and quickly changed the banner.
The site itself. Everyone pretty much hates the admins and openly badmouths them yet haven't abandoned the site. Although for some it's less "the place sucks but I don't want to be unpopular so I'll stay" and more "because the place is popular and has few alternatives, I have to stay to be able to interact with the fandom regardless how I feel about the site's policies".
Memetic Mutation: How many of the avatars get created, let alone some other things.
Krystal can't enjoy her sandwich. This one has spread to the whole fandom and possibly beyond.
FA's downtimes are practically a meme in and of themselves.
Uncanny Valley: The site has photomorphs. Shouldn't that be enough info?
Vocal Minority: This is the Furry Fandom. Ask most people who don't go there and they'll tell you about how messed up everyone is and casually Hand Wave mentions of people who don't post mature art, also post art on DeviantART or sites like Art Spots, or only draw stuff because they need to put food on the table.