Star Trek: Deep Space Nine/Heartwarming

• The moment in "The Way of the Warrior" where Worf and O'Brien reminisce about the events surrounding "The Best of Both Worlds". It becomes a Tear Jerker when they start eulogizing the Enterprise-D because, in a meta sense, they are also eulogizing the Next Generation.

Worf: We were like warriors from the ancient sagas. There was nothing we could not do
O'Brien: Except keep the holodecks working right.

• The episode "In the Cards" is one of the franchise's few truly successful comedy episodes, focusing on Jake's attempt to cheer up his father in the wake of the looming war by getting him a mint condition Willie Mays rookie card. This ultimately involves both him and Nog having to do favors for a bunch of other people: do jobs for O'Brien so he can go kayaking on the holodeck, retrieve Bashir's childhood teddy bear after his ex-girlfriend stole it, punch up an important speech for Kira, and fix distortions in Worf's collection of opera recordings. At the episode's end, we see the results of all this as Captain Sisko records a log entry that somehow people on the station seem happy again. Finally, he receives the hard-won card from his son and wraps him in a huge hug.
• The end of "The Assignment", after O'Brien saves his wife Keiko from a disembodied alien that had possessed her in order to blackmail O'Brien into sabotaging the station in an effort to destroy the Wormhole. Lovely exchange between those two at the end;

Miles: You don't have to talk about it if you don't want to.
Keiko: It helps to talk about it. Besides, I never want to forget how you fought for me.

• • Also from "The Assignment" there was the subplot about Rom joining the station engineering crew. After showing unwavering loyalty to O'Brien in his struggle to save Keiko, even keeping the faith when he was arrested for sabotage and O'Brien was forced to let him take the blame, he is rewarded at the end when O'Brien promotes him to the day shift in gratitude. It's quite genuinely endearing.
• And while we're talking about Miles and Keiko, there's a sweet scene from the second season ep "Rivals", in which O'Brien is psyching himself up for a racquetball match against Dr Bashir, who had beaten him soundly earlier. Keiko stands beside him, assuming the attitude of a samurai's wife as her husband prepares for battle, while reminding him, "Remember, Miles. Win or lose, tonight we celebrate." Before he leaves, Keiko presents Miles with a Japanese silk scarf scented with her perfume. She wraps the scarf around his head, kisses him and says, "Kick his butt."
• The entire episode "The Begotten", where Odo plays Dad to a baby Changeling, especially the moment where it imitates his face. And bonus heartwarming in that the experience reconciles Odo with his own father figure in Doctor Mora Pol and it gives him back his shapeshifting abilities as a parting gift.
• Virtually any moment with Odo and Kira after they get together is a heartwarmer, but if you want to know what real love means, watch this exchange from "Tacking into the Wind":

Garak: I am afraid he's been hiding the true extent of his illness from you for some time now.
Kira: I know.
Garak: You do?
Kira: I love him, Garak - did you really think I wouldn't notice?
Garak: Then why the pretense?
Kira: Because I also know he doesn't want me to find out about it. If he wants to put up a brave front and protect me from the truth, then fine. If that gives him one last shred of dignity to hold onto, then I'll go on ignoring what's happening to him until the very end.

• • Any part of this story arc ("When It Rains", "Tacking Into the Wind", and "Extreme Measures) is chock-full of these, mostly due to the awesomeness that Kira and Odo bring to any scene. Special mentions go to the beginning scene of "Tacking Into the Wind" with Odo and Garak, the above-quoted scene, the end of this episode where Kira is so focused on Odo when he collapses that she seems to barely notice that she is being held at gunpoint, and the opening scene of "Extreme Measures".
  • Also, when Odo and Kira finally hook up. It's almost like a CMOF meets CMOA meets CMOH. Watch it here
• Lwaxana holding Odo in the folds of her skirt as he regenerated was oddly moving for this troper.
• "Duet". What could have ended up being a rather Anvilicious anti-racism episode managed to be one of the most moving and beautiful episodes in Star Trek history, complete with a Tear Jerker ending.
• "The Visitor" is made of this and Tear Jerker in equal portions.
• Sisko discovering that Jake is teaching Nog how to read in "The Nagus."
• That one episode where Worf sacrifices the mission and the Cardassian defector with valuable information to go back and get Jadzia back to proper medical facilities instead of letting her die.
• Garak and his father Enabran Tain in the Dominion prison camp in "In Purgatory's Shadow".
  • Even more so, the fact that when Tain asked Garak if they were alone, Garak lied about the fact that Bashir was in the room, allowing him to stay and not only witness him reveal the biggest secret of his life but share in one of his most emotional and vulnerable moments. It's easy to miss this powerful unspoken statement of how much Garak trusts Bashir.
• Garak and Bashir in "The Wire", when Garak asks Bashir to forgive him, which he does while holding his hand.
• In "The Quickening" when Bashir seems to have utterly failed... but thanks to his antigen, a Teplan baby is born without the deadly blight, ensuring future generations will be safe.
• In "A Call to Arms" Sisko's speech to the remaining people on the station promising to return before he beams over to the Defiant.
• At the end of "Body Parts", Quark sits in the empty space that used to be his bar, all his possessions and business assets having been confiscated. Rom comes in to console him, and after a little bit... cue practically every non-Ferengi on the station coming up with contrived, mock-cynical, Quark-esque excuses to set up the bar exactly as it was.
• From Dogs of War:

Quark Rom, I want to buy back the bar.
Rom: That's all right, brother, I'll give it to you.
Quark: I suppose you're going to let me keep the five thousand bars of latinum too.
Rom: You're my brother.
Quark: And you're an idiot.

• Rom looks sad*
  

Quark But I love you.
*Rom smiles*

• • Pretty much any time Quark shows affection for Rom counts. He may be a Jerkass, but family's family.
    • Quark risks his life to free his brother from the Dominion and has a key role in the success of the entire war mostly as a side effect of freeing his brother. He was willing to bribe the Dominion everything he had, he even got Zek to offer an official bribe from the Grand Nagus.
• The end of "Soldiers of the Empire", in which Martok invites Worf to join his house.
• The third season episode "Indiscretion" also has one of these for Dukat and his half-Bajoran daughter Ziyal. While he originally wanted to kill her to save his career, the episode ends with father and daughter embracing each other in a big, big hug. Especially heartwarming considering he actually gave up his career and social status by letting her live and openly acknowledging her as his daughter.
• At the end of the Season 7 episode "Take Me Out To The Holosuite", Sisko's Vulcan Rival tries to rub in just how badly DS9 lost at baseball, even if they did manage to score a run. Sisko takes it in stride, enjoying the camaraderie and remembering how much he loved the game, then Sisko's team stand up for him, getting under the Vulcan's skin so bad it leaves him at a loss for words, showing how great the True Companions and Fire-Forged Friends tropes are.
  • Topping everything off with giving Sisko a new baseball signed by every player on his roster.
• The end of Nog's story in "Heart of Stone". After Sisko finally forces Nog to tell him why he wants to join Starfleet, Sisko realises how badly he's misjudged Nog and commits to helping him become a Starfleet officer. Nog is so delighted he hugs Sisko and promises he'll never regret it.
  • And on the greater scale of things, Nog lives up to that promise, becoming a model Starfleet officer who makes Sisko proud. In a way, even though Sisko was happy enough to let Jake become a writer and journalist rather that following in Sisko's footsteps as he'd hoped, Nog fulfilled Sisko's dream in Jake's place. Just to give it some perfect closure, one of Sisko's last acts in the final episode is to promote Nog to lieutenant junior grade.