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.
Harsher in Hindsight: Arguably, this is true for one of the reasons why Razorfang is reluctant to either use Spike's name or give the 'hatchling' his own (Spike later considers it's probably not his real name). It's because one dragon wishing another to call him by their actual name is to imply that they are considered family. Razorfang lost his mate and two young sons, to hunters 'a long time ago'. Even worse that Spike has no idea that what he thinks is a demand for some common courtesy means something else entirely to the older dragon.
Moral Event Horizon: In chapter 10 someone launches a harpoon at Spike while he's in mid-flight and carrying other ponies. Fortunately, it missed.
Tear Jerker: Spike finally giving up on Rarity at the end of chapter 12. Ouch.
The majority of chapter 11 was downright depressing too.
The Woobie: Spike. The poor kid was put through a lot in this story: Fantastic Racism, a duel to the death with another dragon, even attempted murder. Word of God says that he always viewed Spike as this in the series, which served as inspiration to this Fan Fic