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.
Crossover Ship: Played with; there isn't really any shipping between characters of the two different universes, but Shining Armor and Cadance THINK there's something going on between Sonic and Twilight. The few times they bring it up to them, though, they're completely confused.
Tear Jerker: Shining Armor's apology to Twilight over what happened in "A Canterlot Wedding." The Time Eater has him and Cadance in its grip after dealing a serious blow to the mane six and Sonic. Shadow's words from earlier echo in his mind as he fears this may be the last thing he ever says to her.