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.
YMMV: My Little Pony: The Mentally Advanced Series
Adaptation Displacement: Greg says in this blog entry that this is happening to Rainbow Factory, that an increasing number of people think that Greg created the story, and Aurora Dawn was stealing the idea from him. He attempts to rectify this by linking to the original fanfic, and vowing to credit Aurora the character as Aurora Dawn's creation every time she's used, such as in the short "Investment Losses".
Better Than Canon: Many find Dashie's versions of infamous Fanfics much better than the originals, especially Cupcakes and Rainbow Factory.
In "Griffon the Brush-Off", Pinkie tries to spray Fluttershy with aqua regia. Aqua regia is a highly corrosive liquid, able to dissolve gold and platinum.
During "Winter Wrap-Up", Twilight and Rarity's conversation is derailed by discussion of several words with "hippo" (or "hypo") in them; some of those words are rather obscure.
Twilight's description of the perils of intestinal surgery is scarily accurate.
Twilight says that Apple Bloom was "born from consanguineous mating".note Consanguineous comes from the Latin word for blood, and means "descended from the same ancestor". In simpler terms, she's calling Apple Bloom inbred.
Pretty much everything Pony-related Greg and his team make ends up on EQD's front-page nowadays, including Captain Hook the Biker Gorilla, which was begrudgingly given its own post with a descriptor saying simply "You win." Ė apparently a number of EQD's users had also been complaining about the site's pro-Witchcraft bias.
Not that Mentally Advanced isn't also popular. The difference could be due to MAS constantly getting pulled due to copyright trouble whereas RDP, which uses no show assets, stays online regardless.
Nightmare Fuel: Celestia's appearance in episode 8. With ominous music playing in the background, her deep, threatening voice, and Twilight literally screaming in terror in her head while smiling, it's hard not to fear her.