Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Tear Jerker: Zone Of The Enders
"That is the purpose of those who have no life". The fact that ADA says it wih the same calm finality in which she says everything else, adding only a small pause, makes it so resigned and sad.
Zone of the Enders: Dolores, I. The whole freaking half of the last episode.
Also to lesser extent; when Radium said: "No... I can't turn back now. It's too late."