This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Justice League: Doom
Two stand out moments— Bruce being buried alive in the same coffin as his parents' corpses and having to punch his way out, and Green Lantern's method of being taken out is to make him think he killed two people by making a bad call. His soft weeping will have you in tears within seconds.
The Justice League's Darkest Hour montage: Superman falling after being shot, Batman being buried alive, Green Lantern left broken and sobbing, Martian Manhunter burning in agony, Wonder Woman slowly exhausting herself fighting the "Cheetah's", and Flash gradually stumbling as he tries to keep the bomb on his wrist from detonating. The music played during the montage doesn't help.
Hal apologizing to an unconscious Carol, saying he still feels guilty over what she's become.