This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Neverwinter Nights 2
Shandra Jerro's brutal, torturous death at the hands of her own grandfather. 'Nuff said.
Especially since the party shows up seconds after he deals the killing blow, subverting the Big Damn Heroes trope to Hell and back and probably leaving the Knight-Commander wondering whether they could have saved her, if they'd just been a little bit faster.
When you confront Ammon Jerro and make him realize his actions caused Shandra's death, he kneels down and implores her to forgive him. Which she does, if the sudden beam of heavenly light revealing a personal treasure is any indication.
Bishop's eventual fate. Despite all his bravado about it, it's pretty clear that he's terrified by the thought of being essentially erased from existence.
Ammon's and Gann's eventual fates. Ammon will likely be dragged to the lower planes when he dies because of all his Deal with the Devil moments in his quest to stop The King of Shadows. And Gann will most likely end up on the wall for being a Flat-Earth Atheist who is implied to stay that way even if he's romanced by a cleric PC in the best ending. The best outcome for him is to pledge himself to you in the "bind Akashi" ending.
When Neeshka comes to visit you before the trial, she'll offer to cheat by rubbing acid on Lorne's weapons and armor. It doesn't really matter how Lawful you are: you will let her do it, because the alternative is hearing her say the following in the voice of a child who's been told their drawing isn't good enough to go on the fridge:
Neeshka: All right. I mean, I only had to steal the acid out of Sand's shop and avoid his wards, but if you don't need it, you don't need it. Or me.
Gannayev's backstory. He is a child of a night hag, who fell in love with a human, and when she refused to kill his father, her sisters of the coven made her eat her husband, which drove her crazy. Gann is shocked when he finds out the truth. Thankfully, you can exact vengeance on the coven.