This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / The Hunger Games
Even worse, Katniss realizing the muttations are the former tributes, especially who the smallest one is.
Taken Up to Eleven in the movie. After placing flowers on Rue's body, Katniss makes a farewell salute to those living in District 11.
The very premise of Catching Fire. Katniss and Peeta won the Hunger Games! They both survived, and from District 12, no less! They're safe now, and they've got all that food, right? No, they're both going back into the arena, which is not supposed to happen. They won, they're supposed to be safe, and now...
This becomes huge Fridge Sadness when you think about what this might have been like for some of the other Victors. Think having to fight strangers (with a maximum of one person you have even a chance of knowing) to the death is bad? These people are in a position to watch plenty of people they know, who might even be friends or neighbors, fight and die right in front of them, possibly after turning on their own friends in a desperate attempt to live. Even though some of them were planning an escape, it doesn't get much worse than that, not just for the main characters, but for the other Victors, who have already gone through such a traumatic experience and had several years - or even decades - to heal from it, only to be chosen to go back and do it all again!
Katniss says in the first book, when she meets Cinna, that most of the stylists are familiar faces, that they stay constant over the years. Presumably, they thought when she won that they'd be seeing her again over the years, now that she'd be a mentor, maybe even they'd even "get a better district" after the success of the Girl on Fire dress, and now suddenly, she's going back in to the arena...
The female Morphling's death. Oh GOD. When she paints a flower on Peeta's cheek with her own blood and Peeta tells her it's beautiful...
Cinna! The last time we see him, he's with Katniss, just as she's about to enter the arena for the second time... and then a bunch of soldiers come barging in, knock him unconscious, and drag him out of the room before Katniss' eyes, with her trapped and unable to do anything about it.
In Mockingjay, Katniss and Buttercup both breaking down and crying together after Prim's death.
That damn cat made it all the way home from District 13, but it doesn't matter. Prim is dead.
For the record, Katniss and Buttercup mutually hated each other up to this point. But they cling to each other because they're the closest thing they have to Prim at the moment.
The Victor's Purge where the non-rebel victors were tortured and murdered by the Capitol.
How Johanna was tortured in the Capitol. Basically the Peacekeepers drowned her in water and then electrocuted her.
Finnick's death. It's just so sudden and shocking, and then you learn that Annie is pregnant.
The book that Katniss and Peeta make at the end to honor the fallen.
Prim's death. A few sentences, and the entire series suddenly feels pointless.
"I'm sorry, Mags. I can't do it." The fact that Mags committed suicide just to save Peeta is just gut-wrenching.
Made even worse when you realise that Mags was Finnick's mentor, and that she volunteered so that Annie wouldn't have to do it.
Finnick and Annie reuniting in District 13, particularly if you reread the book. You know that they're so happy, but Finnick's going to die later — the thought is just too sad.
The very brutal deaths of Darius and Lavinia were both massive Tearjerkers, even though they were mentioned in passing by Peeta. Darius died when the Peacekeepers cut off his body parts one by one and Lavinia died when the Peacekeepers kept applying electrical shocks to her body until her heart stopped. The whole time, the Peacekeepers kept demanding information, but since both victims were Avoxes, they obviously couldn't say anything. They were just being tortured to death so Peeta could be traumatized.
Katniss giving Johanna the pine needles in Mockingjay. "Smells like home."
Katniss and Peeta's conversation about colors in Mockingjay. Oh God.
Finnick's confession. He's been used as a sex slave for ten years because the Capitol will kill his friends and family if he doesn't go along with it.Nothing else is needed to make it a Tearjerker.
But there is something else. Katniss' reaction.
I want to interrupt the taping and beg Finnickís forgiveness for every false thought Iíve ever had about him.
The beach scene in Catching Fire where Peeta tells Katniss that he knows both of them are planning on dying for the other, but it has to be him who dies for her. Not just because he loves her, but because she has people to go home to. And then he opens his locket and shows her the pictures inside- not her as you might expect, but Katniss' mother and Prim on one side and, of all possible people... Gale on the other. One of the most heartwrenching examples of I Want My Beloved to Be Happy ever committed to paper because, unlike the usual examples, Peeta isn't just giving up on Katniss romantically to let her be with Gale, he's going to give up his life.
My family. My mother. My sister. And my pretend cousin Gale. But Peetaís intention is clear. That Gale really is my family, or will be one day, if I live. That Iíll marry him. So Peetaís giving me his life and Gale at the same time. To let me know I shouldnít ever have doubts about it.
Everything. Thatís what Peeta wants me to take from him.
And when Katniss realises that he's not playing for the camera, these are his true feelings it gets even worse:
"No one really needs me," he says, and thereís no self-pity in his voice. Itís true his family doesnít need him. They will mourn him, as will a handful of friends. But they will get on. Even Haymitch, with the help of a lot of white liquor, will get on. I realize only one person will be damaged beyond repair if Peeta dies. Me.
"I do," I say. "I need you."
At the end of Catching Fire, after Katniss is rescued but Peeta is captured by the Capitol, Katniss goes briefly mad with grief at losing him, she attacks Haymitch and has to be sedated.
Other hands help Finnick and Iím back on my table, my body restrained, my wrists tied down, so I slam my head in fury again and again against the table. A needle pokes my arm and my head hurts so badly I stop fighting and simply wail in a horrible, dying-animal way, until my voice gives out.
The entire premise of the series is a tear jerker. Every tribute in the Games has been taken from their homes and forced to kill others for entertainment. It makes for good literature but, Heavens above, it's a horrible situation. Especially for the careers, who have pretty much been conditioned to kill for the sake of entertaining the people of the Capitol. Sweet Heaven...it's an absolutely awful and equally chilling scenario...it's just...ugh...
Haymitch. By his district, he's deemed as a crazy drunk, but after his trick with the force field in the arena, his mom, brother, and girlfriend were killed. And what did he have to cope with all those years? Just alcohol. He's been forced to mentor District Twelve's tributes every year since his own games and none of them have made it out alive. That means that by the time he meets Katniss and Peeta he has mentored forty-six children only to watch them die horrible deaths for the sake of entertainment, knowing that as their mentor, he was pretty much their only hope for survival. Who wouldn't be a drunk?
Up to Eleven when you realise the last you hear of him, he's returned to drinking. For all we know, he's dead before the epilogue begins, hasn't even seen the children of Katniss and Peeta, and possibly hasn't even seen Peeta return healed. He does help Peeta and Katniss with the book. So he knows Peeta's on his way to recovering, as well as Peeta and Katniss getting a chance to grow back together.
The tearjerker part is the book itself. While it won't be bringing anyone back from the dead, it will keep them living on, forever. And that's more than Katniss and Peeta, and Haymitch and everyone else can hope for those who're already gone.
Katniss' mother. The poor woman lost her husband long before the series even started, had to watch her daughter walk into the Games, lost her home and most of the people she grew up with, was dropped into a war, and then her other daughter died. There's a very poignant line where Katniss says that her mother can't go back to District Twelve even to comfort her remaining daughter, and that she'll probably never be able to go back.
Katniss finding her prep team, who've clearly been tortured, in an underground cell.
Venia: Katniss is not going to hurt us. Katniss did not even know we were here. Things will be better now.
The idea of the Careers. Yes, they're raised to kill. But most of them are older, trained well, and volunteer if their name is not called. They are honestly preventing people like Prim from dying in the arena, instead of watching 12 year olds go to their deaths. The idea of being raised to die for that is heartbreaking.
During the climax of Mockingjay, Coin rallies the remaining Victors she could get a hold of and asks them to vote on something: a Hunger Games with Capitol children as the Tributes. Reading that sentence alone might make you cringe, but she actually preceded it with her saying that many of the rebels want all Capitol civilians to be offed, which would prove detrimental to humanity's population and that this was the alternative. Even though Katniss is beginning to think that Coin set up Prim's death, she can't help but wonder if this was the exact situation the Capitol was in when they first began the Hunger Games. It kind of gives the Capitol a lighter shade of black, since it was their best alternative over genocide.
Katniss and Gale's falling out as friends. The last time they speak in-story Katniss is struggling to see the boy she grew up with, hunted alongside and essentially considered family since his bomb idea potentially killed her sister and rendered her going into the Hunger Games for Prim's protection, and getting involved in this hellish war, meaningless. She can't trust his word that he didn't do it, and Gale himself is torn that he couldn't protect her family like he promised, let alone knowing she will probably never reciprocate his feelings. After that Gale moves on to a job in District 2 and Katniss to 12, and the epilogue never elaborates on their friendship. It's a stark contrast between their relationship in the beginning to say the least.
The end of the first book, Peeta's reaction after the reveal that Katniss had been playing up the romance aspect to keep them both alive during the games, betrayed. Not to mention that Katniss herself realizes, that while she doesn't know quite fully if she may or may not actually love Peeta, does truly care for him, and the fear that she could be, and is, loosing him devastates her.
Out of the corner of my eye, I see Peeta extend his hand. I look at him, unsure. "One more time, for the audience?" he says. His voice isn't angry. It's hollow which is worse. Already the boy with the bread is slipping away from me.
I take his hand, holding on tightly, preparing for the camera's, and dreading the moment I finally have to let go.
When Prim's name is called at the Reaping, she begins the walk up to the stage, horrified but still strong enough to tuck in her shirt as she goes, just like Katniss had told her to a little earlier. Actually, almost all the scenes that involved Prim were tearjerkers of some sort.
Katniss' panicked reaction to Prim's name being called. The one person she lets herself care about, the one person who's safe ...
Right before Katniss is sent up into the arena, she has one last meeting with Cinna, who tries his best to comfort her with a hug. It's at this point that her defenses break down and she's revealed to be a terrified teenager who knows that she's probably going to die in a matter of hours, if not minutes. She doesn't.
After Katniss has covered Rue in flowers, she makes the three-finger-salute. We get to see District 11, where they return the salute, and a man in the crowd (most likely Rue's father) attacks the Peacekeepers, and soon everyone starts fighting. It's heartbreaking. The music doesn't help, either.
When Katniss is still singing to Rue while she dies, the camera cuts to Rue's perspective, showing us a shot of the trees above her. Then, slowly, it gets quieter and quieter until everything is silent. The screen fades to white and you know that the little girl is dead, even if you haven't read the book.
Katniss:(sobbing over Rue's body) I'm sorry...!
Cato just before his death. In the book, he's portrayed as a psycho who gets enjoyment out of the death of another tribute right down to when he dies. In the movie, he's pretty much the same... until he's about to die. We then learn that his motives were to bring honor and respect for him and his District. He was also a career tribute, meaning that he was trained to kill from a very young age, and likely had no choice in the matter. Killing was all he knew. Combining all of these, plus his behavior at the end, implies that he was craving respect and recognition from people, which, in turn, implies that he was abused, neglected, unappreciated, ignored, or possibly all of the above. This may show that he feels the only way to be loved is to win. What's even sadder is, that assumption may have been true.
"Go on! Shoot, and we [him and Peeta] both go down and you win. Go on. I'm dead anyway. I always was, right? I couldn't tell that until now. How's that, is that what they want? I can still do this... I can still do this. One more kill. It's the only thing I know how to do. To bring pride to my district. Not that it matters."
All the kids' deaths are sad. Examples include Glimmer, who dies a painful, stinging death by wasps while screaming in terror; the District 3 boy, who gets his neck snapped by Cato for failing him; Foxface, who wasn't remotely bad and died a really random death by eating poison berries; and Thresh, who is finished off by the mutant wolves after Cato carved him up offscreen.
Or even right in the beginning; the tiny boy with curly hair inside the Cornucopia. He's trying to hide from the bloodbath, and as soon as he tries to escape, he's brutally murdered by Cato.
It's implied (especially heavily in the movie) that Foxface's self-poisoning was intentional. She was reluctant to kill anyone, almost like Katniss, and didn't want to be killed, yet she had to cover up her suicide as an accident so that her family won't get into trouble for her trick. (If you want to know what might have happened to them, Haymitch and Johanna are two particular examples. And mind it these two are not the only ones — they are the only mentioned.) Ain't it heart-wrenching to know that your family isn't secure even after your death — that is, never safe? Then again, it shows the cruelty and ruthlessness of the Capitol (doubling as (doubtly) unintentional Heroic Sacrifice) and further (along with Rue's death) nails down the idea that President Snow's regime "must pay, must fall!"
It's small, but Peeta's version of the bread scene in the movie. Katniss has always interpreted it as an act of kindness, but Peeta's angry at himself because he didn't do enough. He's been berating himself for five years for not doing more, like actually handing it to her. This is the guy who deliberately took a beating from his abusive mother in order to feed a girl he didn't know well in person, and he thinks he didn't do enough.
Haymitch seeing the Capitol citizens give one of their children a toy sword. If you needed any more reason to hate the Capitol and how it makes something incredibly brutal seem fun and exciting, that was it.
Haymitch's expression just seems to barely repress all the anger and turmoil he's probably feeling, being a previous winner of the games and having survived and experienced the whole glorified bloodbath himself.
Katniss gets her own version in the film of Catching Fire, when she sees a young girl (implied to be from District One) who says: "I'm going to volunteer someday. Just like you."
Watching Katniss trying to nurse her burn wound. She obviously doesn't know how to deal with it, and watching her bite down on the collar of her jacket to silence her screams as she dabs on it makes you tear up a bit.
Haymitch's expression as he's watching tops it off. He's not seeing a tribute, he's seeing what she really is: a scared kid in a lot of pain.
Seneca Crane's execution. This guy had to choose between either having no victor or having two, both of which would likely result in his death. Essentially he was backed in a corner, whilst still having the illusion of choice so that he could be held responsible for his actions.
A real life example: the tragic loss of Philip Seymour Hoffman. As of typing, Mockingjay is nearly finished production and he had completed all his scenes for Part I and had 7 days left to complete Part II.
Mags' death in Catching Fire if only for the look of utter despair on Finnick's face. The way he shouts her name as she disappears into the fog is just devastating.
"I didn't get to say goodbye." And the way she just brokenly says "Goodbye" as she's being pulled out of the room.
Katniss saying her goodbyes in the first film, especially to Prim.