This is based on opinion. Please don't list it on a work's trope example list.
Tearjerker / Tales of the Abyss
If you think that the guy who came back was Asch, then Tear's tears at the end can totally be considered this as she realized that Luke really is dead, and she'll never see him again.
Imagine this: you are a lonely kid who is forced to act way more mature than you actually are and everyone criticizes you for not acting as they want you to and can't wait for you to "become your real self". Then one day someone comes along who actually treats you well, doesn't dismiss your capabilities and treats you as an actual person instead of a cheap version of the "real" you. You understandably become very attached to this person and would do anything for their sake. Then you find it out it is all a lie, that said person you care for and thought cared for you never even saw you as a person and, in fact, you are are a cheap copy of the real person. And you find that out when said person makes you destroy an entire town killing thousands of people. Thinking of it this way makes the whole situation with Van and Luke a horrifying and cruel situation for such a young child to go through.
At Luke's lowest point he finds out he's a clone and his childhood that he thought he forgot never happened., the person he respected and admired the most had been lying and deceiving him all along, he killed ten thousand people, everyone hates him, they prefer the original over him and the only person who might care is having her doubts.
Asch's reveal is made even worse in the anime as you watch Luke relive all the hints leading up to his shattered identity as a replica - being unable to regain his memories, Legretta calling him a defective thing - in the middle of a total meltdown.
The worst part is probably playing a second playthrough and knowing what's going to happen but not being able to do anything about it.
The direct aftermath of Akzeriuth is bad, especially if you pay attention to the voice acting (and in the anime the animation makes it more clear): Luke is having a full on breakdown and considering later revelations like him actually being seven it's obvious that he needs some kind of support...however, his No Social Skills and the freak out he's going through means everyone instead walks away from him. Leaving him alone except for Mieu...
If that part of Abyss makes you cry, then...well...here's hoping you didn't get attached to some of the other characters.
Ion's death. If you can believe it, it's even worse in the anime - at least in the game, Mohs is right there for you - and the party - to focus their Unstoppable Rage upon. In the anime, he leaves without taking the chance to gloat, letting the event hit you in the gut with all the force of a sledgehammer.
Ion's Memorial Service. Anise asks Tear to sing her Fonic Hymns, saying that Ion loved them, and the rest of the party convinces her that her songs can be a prayer to the departed. She agrees, even though she doesn't fully understand all of the parts of Yulia's hymn. Leads to a heartwarming moment, as Tear finishes singing, the voice of Ion thanks her and unlocks the Fifth Fonic Hymn: Judgment for Tear.
Florian, another of Ion's replicas, is very heartwarming, specially in his relationship with Anise, but it can be quite the player punch seeing him acting like a child and using Ion's clothes, especially since, unlike Sync, you never forget he is just like Ion, just a lot more naïve.
The Tower of Rem. This Tower's arguably worse than Symphonia.
Not just the Tower of Rem, but the scenes preceding and following it, as well. Tear is heartbroken knowing that Luke is going to die and then Asch tells Luke to die in his place. After realizing that he wants to live, Luke finds out that he's actually dying; the hyperresonance created such a tremendous strain on his body that his fonons are separating and he will eventually fade out of existence. He doesn't want anyone to know because he's afraid that they'll treat him differently.
Even worse is the timing. Luke finally realizes his own self-worth, and truly wants to live, and keep on living... and learns, right at that moment, that he is going to die. Slowly, but inevitably, and before his time.
How Tear acts as Luke is about to make his sacrifice also qualifies when you consider how much she's usually in control of her emotions. Despite promising Luke that she wouldn't interfere with his decision, when the moment actually comes her resolve breaks and she runs to try and stop him such that Guy, who incidentally was easily the most vocally opposed to Luke sacrificing himself, actually has to hold her back. It's really telling how important Luke has become to Tear that she would lose control of herself so much despite having said before she would accept his decision.
The conversation with Jade before the Tower, who has just proposed that Luke commit mass suicide, rather than Asch. Luke asks Jade if that's really what he thinks is best, expecting a 'yes'. Jade does say yes, and then...
Jade: That's what I would say if I was an emperor, with a country and people to look after. As your friend... I feel compelled to stop you.
The ending. First with "You have to come home. You have to! I'll be waiting... always," then "Luke...I love you," and then the happy tears after the credits.
That ending, depending on how you interpret it, it's a big case of Downer Ending or Bittersweet Ending because Luke dies. The contamination sidequest reveals will choke you up when Jade says the only things that will be left of Luke are his memories. It doesn't help that after the credits, everyone's happy (save for Jade, whose really ambigous expression can be interpreted as happy or not so much) and thinks it really IS Luke.
The ending is a different flavor of bittersweet depending on how you interpret the identity of the person- if it's 100% Asch, then Natalia gets her beloved back, but Tear doesn't. If it's 100% Luke or Luke's mind in Asch's body (the most common), Tear gets her beloved back while Natalia doesn't. Either way, his existence will serve as a constant reminder of what might have been to the girl who loses out- especially sad for Natalia if you went with the last one.
Luke's turning point, especially the part where he realizes everyone prefers the original over him. "It's no wonder everyone got sick of me and left me behind." The start of a nasty inferiority complex for Luke...and one that can resonate with some people - and so, Luke's decision and the resulting Important Haircut leads to a very touching moment.
Asch's death. Even after spending the entire game blaming Luke for taking over his life, he STILL ends up sacrificing himself so that his replica can move forward. He finally accepts Luke for who he is, and puts his faith in him as he's dying ("Looks like I had a little trouble... The rest is... up to you.)
The scene when Tear confronts Luke about his condition and the following skit: when Luke is afraid of being treated differently because of he's eventually going to disappear and Tear is angry at herself for being powerless to help Luke.
Tear's voice when she tells Luke he has to come home is worse when you can clearly hear in her voice that she's utterly distraught, considering she sounds like she's been crying, but there's not a tear on her face.
"Class M and Class I's first and final cooperation together." Made all the worse in the anime.
The death of Arietta. In the anime, it's even more heartbreaking as Arietta hallucinates Ion and her animal family with her, reaching out to them, and then dies at that moment. It's even sadder by the fact she died without ever knowing the Ion she knew and loved was already dead.
"You're the only Ion that matters to me." She's a real asshole to Luke after Akzeriuth, but when the chips are down, Anise is a good person. Guy also deserves a mention for one of his lines during the handful of introspective scenes he has with Luke in Aramis Springs: "Replica or not, you're real to me."
Her treatment of Luke hurts when you realise why she's the harshest to him of your other five members- Anise is constantly trying to make the party hate traitors so they'll hate her.
Frings' death. It's bad enough as mandated by the plotline, but you have the option of spending an entire long sidequest chain getting him together with General Cecille. To have done all that work for them, and seen the honest joy as they overcame the obstacle of being in opposite armies, to talk to Cecille who is so happy that she and Frings are going to be able to marry... it makes his death really hit that much harder.
Oh yeah, it's also on Nightmare Fuel page, but the kid in Akzeriuth who dies by sinking into the mud.
You also meet his mother later in the game. It's as depressing as you might imagine.
Mingled Nightmare Fuel and this, but the fact that there are people who just accept deaths and especially the war because 'the Score said it would happen'.
Luke's journal entry from the night before the final battle. He almost decides to tell Tear that he loves her, but the fact that he doesn't have much time left stops him believing that all he'll do by telling her is break her heart when he does die.
And then she tells him she loves him right before she's forced to leave knowing that it's overwhelmingly likely that he'll die releasing Lorelei and she'll ever see him again.
The journal entries from Luke detailing his dilemma over his impending death.
Luke: Tear told me not to keep anything from her anymore. Yeah, I guess. Now that she's learned my biggest secret, I don't have anything...well, only one thing to hide from her. Thanks, Tear.
There is a flashback in the anime where after being kidnapped to Choral Castle Asch ventures home to his parents, only to be shooed away by the guards. He climbs up a fence wall to discover he was replaced by replica Luke. His heart just breaks.
A small blink-and-you'll-miss-it around Belkend. Guy separates himself from the party, saying that he's going back to where Luke is. Asch's initial reaction is "Guy... why?". It's subtle, but there's a definite hurt note in his voice at that moment. Asch is hurt by the fact that, someone whom he considered a friend of his, was actually choosing the replica.
Hell, the entire game from about the time Akzeriuth is destroyed to the end is just one big Tear Jerker after another, with little relenting between it all unless you're doing the sidequests. You could make a solid argument the game gave you Jade just to mitigate the emotional assault the game wreaks on you. To elaborate, if you don't do the sidequests, After Azkeriuth is destroyed and Luke is totally abandoned by his friends, you find out Mohs is still trying to push the war by kidnapping Ion and Natalia. Once you rescue them, you then find out Guy wanted to kill Luke all along. Then you learn St Binah is sinking and it's entirely possible soon after that that you can kill Noelle's brother, Ginji. After a small breather, you find out Natalia isn't even the real princess and Anise is fired from protecting Ion, who she is in love with. When you get to Baticul, Natalia is rejected by her father and you are run out of the capital (but the townspeople love her enough to protect her with their lives, so this isn't exactly cheerful). Not too long after they make up, though, is the utter massacre at Sheridan and you find out that Tear is dying, which there's literally nothing anyone can do about. You kill the God-Genreals and Van and all is sunshine and bloody rainbows, but Van's sword's been nicked and Luke has zero self worth right now because the only person in the manor who likes him is his mother. Immediately after learning that none of the God-Generals died, Frings is killed BY MOHS, and as noted above this is even worse if you do his sidequest. Then the deadly Miasma is back, you learn Anise was blackmailed into betraying you, and Ion straight up dies, but at least Tear isn't dying anymore! Then you find out Largo is Natalia's father, but don't tell her, and then Sync shows up to be an ass and remind you Ion is dead! And you murder Arietta and you feel like you basically put someone out of their misery more than anything. THEN, after Luke has obtained self worth, he is essentially forced into sacrificing his life and he stains his hands with more blood. Then Natalia learns the truth of who her father is, Van is brought back, and you have to kill Natalia's father! Oh, and after that, you find out the Score of Prosperoty has foretold destruction all along. Then you murder Legretta which is hard on Tear, and then Asch dies! And then you kill Van, and Luke has to die for real this time! Almost nothing happy happens between all of that! This game doesn't want you to be happy, and I didn't even mention everything soul-crushing, like the fact that Mohs made replicas of Guy's older sister, of Iemon, and General Frings just to be an asshole, and the piss-poor treatment of replicas, and the entire thing with Professor Nebilim.