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.
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.
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.