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: Address Unknown
Hilarious in Hindsight: Twilight's freakout on the train where she imagines a ridiculous worst-case scenario of what could happen if she comes out to her friends somewhat resembles Pinkie's similar scene in "Wonderbolts Academy", right down to the line "...and it would be ALL HER FAULT"
It was also very similar to Apple Bloom's freakout in "Hearts and Hooves Day" where she imagines that if Big Mac and Cheerilee stay under the influence of the love poison, it will result in Ponyville becoming "a town full of starving idiots."
Nightmare Fuel: Celestia's description of just how horribly the ancient spell Twilight was using could have gone wrong.
Sweet Dreams Fuel: Pretty much every chapter from the third onwards has some aspect of this.
The Woobie: Derpy, especially during the first three chapters.