Tearjerker / I Among Dogs

• Nathan at the start having brief moments of hopelessness due to his stranded situation.
• Nathan in general feeling completely alienated and immigrated by the other bipedal dogs which goes on until the tenth chapter.
• For the majority of the fanfic for six chapters, Nathan is left severely worried about the fate of his parents.
  • And then, cue Chapter 7 where his parents have finally been found... only to discover that the plane crash had killed them, rendering him an orphan.
  • This becomes a lot more depressing once you realize that Nathan is the only human being in Canistralia.
• The memory Nathan has of his father standing up for him against a school bully in the following chapter.
• The whole climax of the 14th chapter, just before Nathan is about to kiss Hailey after their first date, the latter quickly goes off to prepare better for said kiss, promising to be back. After being left waiting for longer than necessary, Nathan eventually finds Hailey making out with another dog, her boyfriend. The Husky straight up admits to Nathan that her feelings for him was all a lie and was all done just to screw with him all because he's a human, before delivering Nathan a cold slap across the face to rub salt in the wound.
• During the chapter, 'Babysitter Putdown', Bluey unintentionally asks questions to Frisky about Bosco just days after Nathan's humiliating experience with Hailey, much to Bingo's chagrin whom tries to make her stop. It keeps going until Nathan finally snaps under the built-up stress and explodes into an enraged outburst at Bluey. He immediately regrets this.
• Nathan's monologue to Frisky:

  Nathan: It’s like… whenever you hear a song or watch a scene from a movie or a TV show about a broken heart. They’re right. Even if it doesn’t hurt as much as it did at that night, I still feel something bad where my heart is, like it’s cracked.

  • Believe it or not, this is actually Truth in Television. It's called Takostubo cardiomyopathy or more aptly named, "Broken Heart Syndrome" - heavy chest pains and symptoms similar to heart failure due to severe emotional stress.
• The majority of chapter 16. Poor, poor Mackenzie...
  • To start, we are finally revealed why Mackenzie doesn't trust humans let alone Nathan. He was involved in a war between dogs and humans when he was just five months old. To prevent him from fearing other dogs for the rest of his life, his parents had to lie and tell them that it was humans who caused the war.
    • Then comes his reaction once his parents tell Nathan who actually caused the war to begin with.
    • He then regrets how he had been initially treating Nathan the whole time, possibly fearing that the human might hate him.
    • Mackenzie's nightmare near the end of the chapter can certainly count as both this and Nightmare Fuel as well.