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.
Author Avatar: Sho seems to be one. Those more critical of the fic have noted that Sho seems to fill all of the 'necessary' roles for a replacement love interest; he acts as a close companion to Hanako for the beginning of the story and ends it alongside a subversion of the Just Friends trope. The fact that the author has Hanako as his forum avatar doesn't help.
Tear Jerker: Hisao's death and the repercussions it has on various characters. The worst part is seeing Lilly fall to her knees before his grave and say to herself, while sobbing so much that she's almost unintelligible, that he promised never to leave her.
Hanako may be incredibly successful, but she's also lonely, depressed, and haunted by her memories of her angry outburst at Hisao which ends up being the last time they talked, and Hanako is nearly as badly damaged by his death as Lilly is.
Lilly and Hisao blame themselves for driving their mutual friend away. Hisao dying of a heart attack nearly breaks Lilly.
Sho. His mother died in childbirth, his father committed suicide, he's been in and out of foster homes his entire childhood and is about as reclusive as Hanako was.
The Nakais, mentioned in passing, also qualify. Considering how they reacted to Hisao's first heart attack and his condition being diagnosed, one has to imagine how painful hearing about their son's death would be.