"Mr. Hankey, the Christmas Poo" is the first episode in the whole series where Kenny does not die, and proud of it: throughout the whole episode, Kenny is put through all sorts of dangerous situations where he could easily die, yet he survives. As the episode comes to a close, Stan and Kyle feel like they're forgetting something, as Kenny is quite blatantly still alive. Then the words "THE END" appear above the boys. Kenny cheers, and the credits roll. Oh, and it was Christmas. How's that for a first Throw the Dog a Bone moment for Kenny?
The AV Club's review of the episode frames this as a Heartwarming Moment in a meta sense, too, seeing as Parker and Stone were considerate enough of our love of Kenny-death to keep him walking the tightrope for most of the episode:
Butters... Oh so much. Most of his scenes and a number of his focus episodes (see below) fall under this. More pronounced given he is surrounded by Too Stupid To Live adults and Jerk Ass friends
The South Park episode "Raisins" contains an atypical moment in the series where Butters, up until now little more than the Butt Monkey, is crying because he had his heart broken by a Raisins girl who only liked him because the Raisins girls are trained to flirt with boys for extra tip money (and Butters, naive as he is, took this to mean that she really did like him). A group of goths attempt to get him to join their depressing group, but Butters refuses, stating that even though he's depressed over having his heart broken, he feels happier knowing he can express that kind of pain and would rather be mocked for being a wuss who cries a lot instead of a "faggy Goth kid." For such a cynical, satirical show, it was oddly uplifting and was a turning point for the character.
The line that really makes the moment is Butter's brilliant insightful revelation that, as he puts it, him being that sad means that he was happy enough in the first place to have managed to become so sad. The sadness he was feeling was equal to the happiness he felt previously, and he's only that sad because he lost something that had made him THAT happy. He looked at his sadness and correlated it to the happiness he had experienced. If it didn't matter to him, and if it didn't make him so happy, he wouldn't be nearly as devastated. So he decides that it's worth being that sad, because it means he's capable of achieving happiness just as great. Simple enough, but it's the kind of thought process that can change a person's life around.
Cartman crying and screaming trying to revive Kyle in the Imaginationland Trilogy. And grinning and laughing with joy when he succeeds.
Cartman: Goddammit, Kyle, you never walked away from anything in your life! Now fight! Fight! Fight! Right now! [begins to break down] Fu-hight! Fu-hu-hight! [pounds Kyle's chest hard] Fight!
Butters gets another one in "Cartman Sucks" in which Butters is sent to a church camp for sexually confused boys and tries to save his best friend, Bradley, from suicide by accusing the camp counselors of being confused and projecting their insecurities on the children (despite not knowing what "confused" means in terms of sexual orientation).
Earlier on, despite Bradley getting him into trouble with counselors for stashing men's underwear catalogues, he forgives him very nonchalently and suggests cheerfully that if they continue their work maybe they won't be confused anymore. The sheer kindness of this actually leads to Bradley gaining affections for him.
And then there's the episode "Kenny Dies", which is a subversion of a Heartwarming Moment. Cartman spends the entire episode crusading to lift the ban on stem cell research to save Kenny from an degenerative muscle disease. Meanwhile, Stan is freaked out by Kenny's impending death and is unable to face him. When he finally is able to, he races to the hospital, only to learn that Kenny died, his final words being "Where's Stan?" And Cartman? He didn't care about Kenny at all, he just wanted to make money selling the aborted fetuses he found at the beginning of the episode and use the medical technology to clone a Shaky's Pizza.
Specifically Kenny's decision to go back to hell to save his friends.
Kenny comforting Satan while stuck in hell was surprisingly heartwarming. That and him telling Satan he shouldn't let Sadam bully him.
"Good-bye, you guys."
Then we get to see everyone restored and singing a reprise of "Mountain Town" as Kenny's finally allowed into heaven.
The Mother's: Cause Terrance are Philip are sweet.
Sheila: (hugs the brothers) Super Sweet!
Season 15's finale, "The Poor Kid" has this one with Kenny as Mysterion consoling his sister upon being placed in foster care.
Also, this episodes shows that you DON'T fuck with Karen McCormick.
It may not have been treated as the least bit heartwarming but having Kenny back at the end of "Red Sleigh Down" was kind of nice. On a similar note, so was having Cartman channel Kenny's ghost from "A Ladder to Heaven" to "The Biggest Douche in the Universe".
A lot of "The Death of Eric Cartman", in which Cartman actually shows some sincere decency and regret for past actions. Especially heartwarming is his relationship with Butters through the episode. Of course, at the very end things return to normal and Cartman reverts back to the Jerk Ass everyone loves to hate, but the episode was heartwarming all the same.
One scene in particular is the scene where a tearful Cartman tells his mother, through Butters, that he loves her and wishes he had been a better son. She's so moved that she begins to cry, causing Cartman to cry more, and eventually even Butters begins to sob along with them.
At the end of "Stupid Spoiled Whore Video Playset", when Mr. Slave delivers a speech about how parents need to do better in being role models to their children, thus proving his wisdom... right after outwhoring Paris Hilton.
Kip GODDAMN Drordy from "You Have 0 Friends." The kid had a sad clown poster on his wall and spent all his time looking sadly at his friendless Facebook page, and was just so ridiculously happy that Kyle was his Facebook friend. At the end, he got all Stan's friends.
How about "It's Christmas In Canada"? Kyle went to great lengths to get Ike back by traveling to Ottawa with his friends, a Mountie, a French-Canadian mime, and a Newfoundland fisherman, to the see the Prime Minister (in an homage to The Wizard of Oz, no less) because of the respective laws of Ike going back to his birth parents, Mounties being forced to ride sheep in lieu of horses, wine being outlawed, and a ban on sodomy. When they arrived, the guard refused entry, and the boys started crying, and the guard felt so bad for them that he decides to grant them entry. It turns out that the Prime Minister was Saddam Hussein in disguise and the Canadians proceed to beat the crap out of the villainous Iraqi dictator, and in the end, the laws are null and void, and Kyle and Ike are reunited.
Although the effect is diminished somewhat by the fact that they were just going with Kyle so they could get presents at Christmas, and didn't give a damn if Kyle would never see his brother again and Saddam remained in control of Canada.
A lot of the moments where Stan and Kyle's friendship is made clear qualifies as a Heartwarming Moment. Once such moment took place in the episode "Ass-Pen", some time after Kenny was killed off for real, when Stan was planning to race an experienced skier down an extremely dangerous slope.
Kyle: Look, Stan. When Kenny died I learned how important friends are. I'm not gonna lose another friend.
Timmy's relationship with Gobbles, a turkey with disabilities, in the Helen Keller school play show. Especially when he goes to sleep and Gobbles hops up to sleep beside him.
The ending of "I'm a Little Bit Country," more on a meta-level. One could not really care less if the Jerkassuseless adults were killing each other or not, but the overall message it carried was very heartwarming.
Randy walking with Stan into the sunset in "Bloody Mary," discussing how much alcohol Randy should drink for it to be considered "in moderation." One of the few moments on the show that actually feels human, and a season finale to boot.
The last song in "Mr. Hankey'sChristmas Classics" is "Have Yourself A Merry Little Christmas," and unlike the others it's unaltered for Rule of Funny. Around the line "happy golden days of yore," there's suddenly a mini-Montage of some of the South Park females, followed by them and others crowding around Author Avatars Stan and Kyle during "faithful friends who are dear to us." All of those characters were originally voiced by Mary Kay Bergman, who committed suicide shortly before the episode was produced.
During "through the years we'll always be together," the four boys throw their arms around each other's shoulders in a rare moment of full group solidarity so nice it's only partially ruined by Kenny's death during "if the Fates allow."
It's always nice when Butters gets thrown a bone. At the end of "Hell on Earth 2006", he not only manages to get Biggie Smalls to Satan's Halloween party, but gets to boogie on the dance floor (in his jammies) with him and everyone else when Satan decides to stop being a spoiled brat and let everybody in, rather than just those who received the special invitations.
Near the end of "AWESOM-O", just when the military soldiers are about to kill Cartman (who they are unaware AWESOM-O is in disguise), Butters saves him and pulls an awesome Big Damn Heroes moment, begging the scientists not to hurt AWESOM-O and how much he means to him. The entire squad of hardened soldiers are left in a state of tears. That is, until Cartman accidentally farts and is forced to reveal his true identity and get embarrassed.
In a really bizarre example, one of the Christmas songs starts with Hitler crying over not having a Christmas tree in song. It's pretty depressing, even if it is Hitler. Satan comes in and cheers everybody up with a happy song, even giving Hitler a wrapped Christmas Tree. Mostly played for laughs, but the whole "no one deserves to be miserable on Christmas, even Satan and Hitler" message behind it all is really touching. Hear the song here.
"Mecha-Streisand" features Robert Smith, who is one of the only famous people not made fun of by South Park. Robert Smith himself was touched by the episode, especially when they call him, "The best person ever."
It's a little weird, but I thought it was sweet that Ike ran to Kyle for help when he was seeing ghosts in "Dead Celebrities." It may sound messed up, but it shows how close they are and that Ike feels so safe with Kyle.
The ending to "Crack Baby Athletic Association".
Though the episode itself was soul-crushingly depressing and deserves to be on the Tear Jerker page, the fan reaction to "You're Getting Old" has been pretty touching. You have people who have been so touched by this seemingly asinine show; they are depressed, they are sad, but as a fanbase, we are pulling together.
From the episode itself, Cartman and Kyle smiling pleasantly at each other in the ending montage. Heartwarming in a weird way, definitely.
The episode "Broadway Bro Down" reveals to Randy that men sit through Broadway musicals with their wives because they use Sub Text to Brainwash them into giving blow-jobs. By the end, Sharon is understandably pissed at Randy for all that, who goes from "pretending to agree with her" mode to "genuinely apologetic" mode. The heartwarming comes when Sharon decides that she still likes Broadway musicals despite the brainwashing, since all it does is make her make Randy happy, bringing them closer together. Considering the end of "Ass Burgers", in which they decided to live together in an unhappy coexistence because Status Quo Is God, seeing them have something that bonds them and bring them happiness was very moving.
The Poor Kid shows one important thing, don't fuck with Karen McCormick, otherwise Kenny will kick your ass.
Even beyond the beatdown, the fact that he dresses up like a superhero to make his scared little sister feel protected (something that, according to their conversation, was a regular occurrence even before the latest incident) is just fantastic.
From the same episode, a small CMOH but worth a mention is Kenny holding Karen's hand on her way to class.
And also him hugging her as she is crying while being interviewed by their incompetent case worker.
Season 6's episode "Simpsons Already Did It" has Chef, under the assumption that the boys had raped and killed Ms. Choksondik, packs their clothes and plans to go on the run with them. Hilarious, but also heartwarming when you realize that he was willing to give up his life in order to protect the kids.
...even if they would have done such a horrible thing.
A small one, but in "Fun With Veal", when the kids (led by Stan) stage a lock-in in Stan's room to protest the slaughter of calves into veal. When the parents decide not to interfere or feed them in order to get them to drop the protest, Liane sneaks the kids some food.
In the same episode, Cartman is given complete control over the situation when he easily manipulates the negotiator into giving him anything he wants (except North and South Dakota). Despite the fact that he initially wanted no part of their protest, has no problems with veal, and thinks he has become the thing he hates (a hippy) it's Cartman who actually ends up saving the calves. By forcing the word "veal" to be changed to "tortured baby cow" there is no longer a market for veal, and the calves are allowed to grow up in safety.
In "A Very Crappy Christmas", while Kyle and Ike are sleeping in the hallway waiting for Mr. Hankey to show up, Kyle's parents quietly come in and put the sleeping children to bed, while a chior humming "Silent Night" plays in the background. A stark contrast from the insane Moral Guardian we knew just a season before.
In "Cartmanland", Kyle watches Cartman get all sorts of wonderful things, and the stress of a Jerk Ass like Cartman getting his own theme park makes him horribly sick, and he loses his faith and his will to live. But what's sweet is that Stan knows him so well that he brings him all the way to Cartmanland to see Cartman lose everything. Kyle recovers pretty sharpish when he sees that God gave Cartman gifts to take them away, just the same as he does with everybody else (at least that's how it works according to Chef).
In "Ladder To Heaven", the boys try to build a ladder to heaven to ask Kenny where he put the ticket stub for the candy shopping spree they won. Oh sure, it's just candy... but they still think you can build an actual, physical ladder to heaven. Kinda cute, even if it is more shallow than the grown-ups think. And all the time Cartman is channelling Kenny's memories.
"Cash for Gold": the parts with Stan and his grandpa. 'Nuff said.
Speaking of such, while heartwarming is probably the last thing that would come to mind when one would tell another to kill themselves, when Dean threatens Stan with a lawsuit, Stan says he doesn't care about what happens to him as long as his grandpa is satisfied. So even if Stan was fined and/or arrested over Dean killing himself, he would fully accept it if his grandpa was fine.
Especially with it.
In "Jewpacabra", after Cartman has been chained in a dark, empty park at night in a bunny costume, doused with blood, shot with a tranquilizer dart, and forced to suffer through one of the worst night terrors of his entire life, Kyle comes along and cuts his chains, walks him home, and tucks him into bed. By the end of the episode, after having suffered through one of the scariest nights of his life, Cartman ends up with a much greater appreciation for Jewish people (even going so far as to convert himself, if only for a day).
Okay, despite Cartman's intentions of avoiding interracial couples, it's pretty awesome the lengths he went to just to get them together. And in the end, they seemed to genuinely like each other; Nichole even says that she doesn't care if people assume they're supposed to be together, making Cartman's reasons moot! Hell, he even makes Kyle happy for a while because the girls seem more attracted to him (this was because he and Cartman were apparently gay, but...). Cartman's a racist asshole, but at least he's a racist asshole who made some people happy.
The final punchline in All About Mormon was surprisingly heartwarming. The entire episode was making fun of Mormonism, but when Stan insults Gary's family and faith, Gary gives him a massive "The Reason You Suck" Speech because his faith gave him good values and closeness with his family.
The concern of the boys- even Craig- at Butters being bullied in "Butterballs". Its really nice to see that the Reset Button hasn't affected everything in the show, and for all that Butters has been through he's gone from an unpopular wuss to actually being good friends with his class, even a fifth member of the main four boys. Before, Stan and Kyle would only be nice to Butters out of pity, but now it's because he's their friend. Made even better in that it shows Character Development in terms of Stan being the most angered by Butters getting bullied (despite what it ended up setting off), when back in the third season's "Two Guys Naked in a Hot Tub" he hated the idea of having to just spend a few hours with him.
Arguably Stan has had the most frequent earnest (unlike Cartman) moments of bonding with Butters. He took him in throughout his tirade against Motivation Corp in "My Future Self and Me", even asking him to run away from home with him, and is brought out of his depressive state from breaking up with Wendy after Butters delivers some rather poignant insight about the humanity of feeling sad in "Raisins".
In "Probably", God gives Satan advice on how to deal with his relationship problems despite everything that's happened between them.
In "Ass Burgers" A drunk Stan for his friend back, while his expressions from happy to sad to Jerk Ass tend to be a case of Mood Whiplash. He actually finally tells his best friend that he loves him.
After leaving him at a clinic, Sharon leaves saying his goodbyes to a deflated Stan and telling him she loves him with earnest concern. This is pretty heartwarming considering Stan is generally treated with No Sympathy throughout the two parter.
Cartman cheering his mom up by singing to her in "Tsst".
To be fair, he did it to get out of trouble.
Cartman's legitimate disappointment at the end of "Chef Goes Nanners", when it is implied he might have enjoyed the idea of Wendy having feelings for him. All in all, it seems more like a Bittersweet Ending, but you have to admit, it's always nice to see Cartman with softer, genuine feelings.
Cartman's genuine gratitude when Kyle saves him from a Golumn-like Snooki during he Jersey invasion, despite Cartman previousy having been on an all-episode crusade against him. "Kyle, you're still a monster..."* Cartman pinches Kyle's cheek and grins* "But you're my monster!"
It's in a twisted way, but Randy and Sharon bonding over being able to kill each other in Minecraft.
After being corrupted by Bebe's breasts in "Bebe's Boobs Destroy Society", all the boys in the class start fighting over her. However after she finally tires of it and finds a way to cover them, they snap out of their primal state, with Stan delivering wisdom (from Randy no less) about not letting them cloud their judgement again, leading all the boys to apologize and hug. Even Mr Mackey expresses out loud how adorable this is.
Amid the endless episodes where they react to him dying with complete apathy, it's rather touching the odd times the boys are genuinely worried about Kenny's safety.
In "Goth Kids 3: Dawn of the Posers", when Michael and Pete come to Henrietta to tell her that the camp was a hoax and that she became an emo on her own, he starts to feel embarrassed and ashamed for doing so. Feeling bad for her, they lie by telling her that they lied and that they destroyed the body-snatching plants, which makes her feel better and makes her a goth again.
Kyle's determination to help Ike in "Taming Strange".
In "The Hobbit" Kane West proclaims that he doesn't care if his fiancee Kim Kardashian is a Hobbit (it.. kinda makes sense in context) - he loves her nevertheless. And Wendy even gives up her crusade to expose the photoshopped pictures of women for the fakes they are, so as not to destroy their happiness.
A meta example in "Make Love, Not Warcraft", the fact that Blizzard not only agreed to help work on the episode, but even went so far as to send some people over to South Park's studio to help animate and set up a private server for the crew to record gameplay with.