I think the reason this works, and isn’t plain depressing, is the mixing of pathos and just plain weird. Eg:

 a 13-year-old basset hound in kidney failure. she was so kind and licked my face as i carried her in from the car for the owner. he was a sweet old man with tears in his eyes. i fed her an entire bag of treats and she kept eating ferociously even after the injection. her chewing slowed down and then she was gone.

 Which is immediately followed by:

a Pacman frog with a proplapsed anus.

An emaciated ferret who had been fighting an auto-immune disease.

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