Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Tear Jerker: I'm a Marvel... And I'm a DC
Watch the first video, which personifies Spider-Man as the best qualities of Marvel movies, in tandem with the short released five years and one Contested Sequel later where Batman and the Avengers express no interest at all in Spider-Man's reboot.
Superman's Heroic Sacrifice at the end of Season One. And Gobby's at the end of Zero Hour. Neither ended up dead, but Gobby's stuck in a rebooted universe. At least he isn't alone though...
Harley's matter-of-fact comment that nobody cares about her. The Green Goblin disagrees with that statement.
Also Green Goblin's heartbroken reaction when Harley gets back together with Reboot!Joker. Anyone who's loved a person who's in an abusive relationship understands how painful it is when even after trying and pleading with them to get out, they just go right back to the same abusive partner.
Deadpool's reaction to Rorschach's death. Specifically, his conversations with Gobby and Death.
Future Lex's guilt over the results of Plan Q. You have to feel bad for the guy.
"Harley....I love you." Who knew The Green Goblin could make you feel so sad.