Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Tear Jerker: Kagerou Project
Ayano's suicide and Shintaro's reaction to it. While Toumei Answer was pretty heartbreaking, it is handled very quickly and matter of factly. But then you realize in Ayano's Theory of Happiness that the poor girl had bonded with most of the cast of the series and they loved her so very much.
Oh, it's much worse than that. Ayano commited suicide because she wanted to gain an eye ability in order to protect Kido, Kano and Seto from her father, who had reached the Despair Event Horizon and killed Haruka and Takane in an attempt to bring Ayano's mother back to life.
Not to mention just how upsetting Lost Time Memory was. In both routes, Shintaro struggles to find himself and move on from her death by keeping the memories of her with him forever. In one timeline, he succeeds. In the other... not so much.
Made even worse when you see Jin's comment in the description. 'I still loved you, today too.…'
The "Groundhog Day" Loop Hibiya and Hiyori are forced to live in Heat-Haze Days. Poor Hibiya is forced to watch Hiyori die in increasingly horrible ways, no matter how much he tries to prevent it. In order to break the loop once and for all, he goes back to the first death and sacrifices himself so the girl could live. And it was a Senseless Sacrifice, as Hiyori sacrifices herself so Hibiya can live and break the loop once and for all.
Also poor Ene/Takane Enomoto, his closest friend and classmate. She had a really big crush on Haruka, but due to her Tsundere personality (that was caused by her disorder) she never really got to express those feelings in other ways than pouts and fists. Then, during a test, Haruka got his final attack and died. This went unnoticed for Takane, who had turned her headphones on while facing the other way, for 20 minutes. When Kenjirou then lied to the heartbroken Takane, telling her that he survived, she finally, with the help of Ayano, managed to get her resolve up and tell Haruka her true feelings. Only that it didn't happen. Because she was KILLED before she reached the hospital. Two years later, in the form of the computer program Ene, Takane met the brought-back-to-life-through-robotication Haruka again, but it turns out he had gotten an Identity Amnesia and didn't remember her.
The Dark and Troubled Past of the characters and how it affects their lives and gain eye powers because of those traumas.
Ene's reaction to Shintaro deleting her in Jinzou Enemy. Despite trying to become a Manic Pixie Dream Girl for his sake and in an attempt for trying to fullfill the role Ayano couldn't do, he still sees Ene as nothing but a shallow program for talking to and deletes her.