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.
Mary Sue: Whether or not it actually counts, since a lot of the "Mary Sue" examples are either lampshaded or all-out parodies.
Which is perfectly fair, given that the Trope Namer was herself a parody of self-insert fanfic.
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.
The change to make themes compact also stirred up complaints. In the past, every theme was separated by clean and adult. The new changes made both clean and adult artwork themes compacted into one setting, which means you can't find just clean artwork only or adult art only; you'll see both kinds at once whether you want to or not.
Note, however, the presence of the "SFW" (Suitable For Work) switch in the upper right corner. When active, it blocks all adult-flagged artwork from view.