If you sided with the NCR and chose right during a certain quest at Camp Golf, you get to hear that the Misfits squad that you re-trained singlehandedly held off a Legion assault during the finale, and the related ending slide is impossible not to smile at.
Depending on your political views, getting the good karma NCR or Independent ending can become one.
The Enclave Remnants. All of them are genuinely tragic characters, and it leaves players with the rather uncomfortable feeling that there were a lot more like them in the Enclave military. They weren't even Punch Clock Villains either, with the semi-exception of Moreno, and even then all he was guilty of was never questioning orders.
Kreger, a father to his men and the main reason the Remnants were able to escape the destruction of Navarro.
Johnson, a soldier who never hesitated to question or disobey any morally-shaky orders. He is found alone in a cave, literally waiting for death to come for him, believing that he has no real reason to keep living.
Moreno, easily the "worst" of the bunch, but only because he never questioned the Enclave in any regard, be it morality or political legitimacy. When the NCR were overrunning Navarro, the one thing he felt true loyalty to was as good as destroyed. Worse? The NCR routinely harasses him in the Mojave Wasteland for squatting in an abandoned house. That he was "squatting" in before the NCR came into the region.
Whitman, who loved flying above all else. When Navarro fell, she was essentially grounded. The only reason she even lives in Novac is because it's close to the REPCONN facility, and she still holds out hope that she can finding working rocket parts.
Dr. Henry, who is possibly the coldest selfless person in the Wasteland. He researches cures for the worst of diseases and conditions, yet does so because he wants to solve them simply because they are problems, not because he explicitly wants to help people, and when he's finished, he moves on to the next. Arcade outright states that Doc Henry has probably saved more lives than he (Arcade) ever will, but that he will probably not be remembered for any of it.
The end of "Crazy, Crazy, Crazy", assuming you take the good end by helping Rhonda. Big, scary Tabitha, who's only screamed about the inferiority of humans and normally attacks you on sight, appears to meet you outside. She's so struck by Rhonda's resurrection that she's practically speechless, and doesn't even know what she's going to do anymore. But she's happy, and walks off peacefully with her friend into the wastes. The ending goes on to say that they adventured through the lands of Ceasar for many years, their tales eventually collected into a book, which was very popular with children. D'awww.
Rhonda: "Mistress Tabitha, we should be heading off. Our journey has been much delayed, but we can catch up if we hurry. Come along, now."
Tabitha: "Yes, Rhonda..."
And during, when you enter the broadcast tower, you have the option to tell Tabitha you're a huge fan of her work. Though she still tries to kill you, she takes a moment to relate her appreciation for the gesture.
If you're nice to Christine during Dead Money, when she says goodbye before the Gala Opening, she thanks you - silently, of course, but in a way incredibly sincere and heartfelt. It's worth muddling through her silent dialogue before that point just because it's so sweet. You and Christine can hold hands, and promise to return for her.
When you with Veronica, she will mention that she really wants to wear a pretty and elegant looking dress. You can fulfil her dream by giving her a formal wear. She will let out an audible squee and thank you for your kindness. After seeing everything that she have to go though, it is heartwarming to see a moment of real joy from her.
Come Fly With Me if you choose the best ending and not side with Legion, when Jason speaks of Chris doing everything in his abilities to help the Bright Followers out. You not only get a rousing speech about both of your achievements but also about how they would be reunited after the game, and Jason will have nothing but praise for Chris when he's rescued by the Bright Followers during the attack on Novac. Making him not only a saint to ghouls but also to the people of Novac, who see him as a saviour from certain death.
Talking Chris out of his Roaring Rampage of Revenge by telling him how the Followers truly did consider him a friend and ally is also quite touching. After the quest, if you talk to him in Novac, instead of bitterly telling you to piss off (which he would do if you completed the quest the good way but didn't convince him he was human), he instead admits that it will be hard, but that the assurances of both you and the Followers have convinced him to use his healthy tech knowledge to help the town.
The radio broadcast you receive at the end of Dead Money.
Vera Keyes: "Wait a moment, before you go. I... we... hope you've enjoyed your stay. Farewells can be a time of sadness. Letting go, difficult. As a guest of the Sierra Madre you know that truth more than anyone. Frederick Sinclair believed that one's life could be made anew every day. That fortunes were more than the wealth in your hands. Love. Life. Family. Those to care for and those who will care for you. To those who know these joys, the Sierra Madre holds little they don't already have. Out in the world, beyond these walls, that is your chance to begin again. I hope that you will return in happier times. Until then the Sierra Madre, and I, will hold you in our hearts."
Through a certain conversation path, you can get God to admit that he really does genuinely cares about Dog's own welfare. Considering who this is coming from, it's pretty touching.
Not to mention the ending where you manage to combine their two personalities into one, perfectly balanced. While the combined Nightkin doesn't remember you or where he is, he still knows that you helped him.
The God ending is also touching. He's finally free from Dog and Father Elijah, assuming control of himself, heals his wounds and later searches for other Nightkins and spoke greatly of the Courier (who had to be VERY patient dealing with him).
Becoming Idolised by the Boomers altogether is rather heartwarming, as you manage to get them to overcome their rampant xenophobia and make them see that not everyone from the Wasteland is a hostile savage. It's rather heartwarming to hear them catch themselves when talking to you and begin referring to you as the "Sav-... Outsider". It's as good a start as any.
Along the same lines, Saving (rather than savaging) Sergeant Teddy for Melody at the Fort.
When you search around many NCR military bases, you will find letters that the soldiers stationed there wrote to their family and friends, many of them are really touching.
A Letter that can be found in the barracks at Hoover Dam: "Angela, my sweet. How slowly time crawls without the touch of your lips. I know you're still angry I enlisted, but I did it for you and for country - I won't have Legion scum anywhere near you or on NCR soil. Those red-skirted pansies don't stand a chance against me, don't you worry your pretty little head. Soon as my tour's up, I'll be home and you'll be in my arms again. I'll have a ring in my pocket and a question to pop. You know what I mean. Yours always, Elaine"
At the end of Honest Hearts, talking down Joshua Graham from executing Salt-Upon-Wounds and as a result, helping him redeem his soul.
Joshua Graham: Sometimes I tell myself these wildfires never stop burning, but I'm the one who starts them. Not God. Not them. I can always see it in my mind. The warmth, the heat. It will always be a part of me. But not today.
From the same decision, in his ending voice-over:
Joshua Graham: Eventually this new spirit would diminish the myth of the Burned Man in distant lands - a small price for the peace it brought to Joshua Graham.
Speaking of Joshua, talking to him earlier in Honest Hearts and listening to him talking about how his Christian faith helps him reconcile himself with his sins is also very touching, especially if you have a religious background.
Joshua Graham: In a world filled with misery and uncertainty, it is a great comfort to know that, in the end, there is Light in the Darkness. Every day we move one step closer to our Lord. We must do our best to follow in His footsteps and teach others how to the same. For many of us, the road is a difficult one but the path is always there for us to follow, no matter how many times we may fall.
Courier: Do you ever "fall"?
Joshua Graham: Every day. Some days... are harder than others.
Another moment from talking to Joshua is finding out that despite the fact that he cofounded the incredibly brutal and oppressive slaving empire, Caesar's Legion, and was perhaps the most cruel and monstrous of them all, his friends and family in New Canaan still took him in and healed him. It's really quite touching that they welcomed him back without any animosity, whereas anyone else in the wastelands would have most likely left him for dead or worse. It all helps him come to his Heel Realization and rekindling his faith.
Joshua Graham: It was as though the Prodigal son had returned. They welcomed me as though I had never left, never done anything to shame them. The fires that had kept me alive was Love. Their love. God's love. I will never be able to repay the debt that owe to them, but I must try.
The good ending of "They Went That-a Way", where you Convince Jessup to release the NCR hostages and assure him you'll convince the NCR leader to not just let them go, but escort them out of the area. Then, when you report back to the NCR leader, you convince him to honor the deal, even though it would be defying a direct order from his superiors, by appealing to his moral integrity as a soldier.
Er. Okay, this one's kinda...kinda strange. But even though your brain is kind of a dick and acts like a spoiled brat at every turn, the epilogue makes it clear that your brain actually misses you and stays in its bound globe out of respect for you.
The good ending of Old World Blues is full of these from the Courier spending the rest of his life helping the people of the Wasteland through scientific advancements to the above example. But perhaps the best is after the credits and all the appliances are cheering you when you return to the Sink. Even the Toaster.
Which turns into a Crowning Moment of Funny when Blind Diode Jefferson keeps cheering for a good thirty seconds after everyone else stops.
It gets better As a Cyborg you can live for hundreds of years, meaning the Courier will see his work make the world a better place
The Stealth Suit MK II in Old World Blues declaring you her best friend forever. It just randomly happens too, she's there for you no matter what.
And if you mess up on the Infiltration Test, it assures you that "I won't screw up next time".
The end of Come Fly With Me. Jason Bright's final speech declaring all who helped him and his group saints shows just how he was able to get so many ghouls to follow him
Similarly, if you go through the extra (annoyingly time-consuming) effort to not kill any of the feral ghouls in the area because you remember how terrible Bright felt about them getting killed, at the end of the quest, you get to see all of them down by the rockets with the normal ghouls, and no ferals left in the building.
ED-E's good ending where he joins the Courier after playing Lonesome Road. ED-E chooses to stay with the Courier because he's the closest thing to a father he has left, what with being aware Whitely might be dead due to disobeying Colonel Autumn's order to kill and scrap ED-E and his brothers. You gave a little orphan robot a home! DAAW!
Actually, it's more likely that the Lone Wanderer killed Whitley back in Fallout 3, either by his/her own hands or with that Kill Sat on the base
It was cut the game before release but still heartwarming. Dr. Keely, the ghoul researcher in Vault 22 was supposed to have a protectron companion, Bohr. Protectrons talk in monotone and never really show any kind of attachment to anything. Except Bohr. He talks to the courier very politely and chews him/her out for being rude. But what cements it as heartwarming is his concern that Keely went to the lower levels days ago and never returned and shows genuine concern for his master, which no other robot besides ED-E does in the game.
Bohr: I couldn't say, exactly. She went down to the lower levels some time ago and hasn't been back since. Do you suppose something has happened to her?
The Courier: Perhaps. I'll go down and look for her.
While traversing Zion Valley you can listen to Follows-Chalk and Waking Cloud making remarks on all sorts of things. While Follows-Chalk makes comments on the questions about the Mojave and you (mostly why you carry all those bottlecaps and how they "jangle like crazy"), Waking Cloud is nothing short of endearing.
Waking Cloud: Zion used to be a place of peace, you know. Daniel says it is holy on the eyes of the Father. I hope someday you will see it as it was.
Waking Cloud: I know you are eager to leave Zion...but perhaps you might find peace if you stayed...think about it, yes?
Waking Cloud: Father, I ask that you guide this man/woman who is the vessel of your will. Show him/her the light of your wisdom and the peace of your love. Amen.
Waking Cloud: I wish you could have met my family. You would like them, I think.
Hearing the grateful praises from numerous NPCs after killing Cook Cook, especially those from his former victims like Betsy and the Westside innkeeper, Pretty Sarah.
The NCR relief efforts. They're quietly feeding their own citizens because their efforts to coordinate with the Kings have been sabotaged. When you explain that you have a friend but you thought he might not get served because he's a Local, she agrees...but then hands you another portion to take back to him anyway. The NCR may not be perfect, but they're trying.
ED-E's recording of Whitley sending him on his journey.
When he lets you hear a recording of him watching Ralphie, you can tell him to keep following you by saying "we've got to fly far and fly fast if we want to get to the end of the Divide". He responds with "determined beeping" accompanied by his battle music.
Recovering Morales' body from the Fiends, and hearing the amazed reactions from the NCR soldiers who witnessed the entire thing. One of them will actually be horrified if you're heavily injured, calling for a medic and wondering at why you "sacrificed your body" to save Morales' corpse. If you respond by saying that you made his wife a promise, he'll tell you that they'll take the body from here, adding that you won't need to haul him back to California yourself, even though he knows you would if you had to.
If you get to a level of Accepted within the NCR, a Ranger will come along and give you a two-way radio. With it, you can call for supplies or support. The ranger who gives it to you basically says that you have done good by them and they have your back. Even if you never use it, it's good to feel like you are never alone out there.
With an Idolized reputation, find a group of NCR Veteran Rangers and chat them up. The idle dialogue includes "ever think of becoming a ranger?", "I'd gladly fight by your side", and "you got my respect". The Veteran Rangers, the most hardcore, badass members of NCR's military, who go through Training from Hell to the point 80% of them wash out during training, practically consider you one of them by reputation alone.
The Kings (Especially The King himself) are nice examples. Most gangs in NV have proven to be rather troublesome, but The Kings? All they want to do is keep Freeside safe and stable for Wasteland wanderers. Ending the tension between them and the NCR is just as nice, as the King puts it:
The King: I think it's time for a little more talkin' and a little less fightin'.
Some of the things the Stealth Suit MK II says in combat count. It'll give you a stimpack if you're low on health and say, in the most sincere voice possible, "Please take this. I don't want you to die."
Finishing any of your companion's quests in the best possible way qualifies, but especially so when it comes to Boone because of how tortured he is by his past. He'll even crack a smile when you choose certain dialogue options while accumulating "like" points to trigger his quest, responding with "I wouldn't hold it against you" when you ask if he minds you taking down Legionnaires and "You and me, we're just a couple of problem solvers" when you talk about fighting the Legion being a solution. At the end of the quest, he'll tell you that it means a lot to have someone with your skill watching his back, not to mention his "That was some stunt we pulled" speech if you take down Caesar at The Fort. Overall, you get the impression that The Courier is the first person in a long while that Boone has trusted and considers a friend.
Raul's quest is just as heartwarming. To put it simply: You help an old man either make peace with his past, or get him to become the hero he once was again. If you opt for the latter, you see at the end he's carried on his quest and has become something of a folk hero who helps those who can't help themselves.
The story of Randall Clark, the Survivalist of Honest Hearts, who goes from a death seeker who lost his family to the (perceived) benevolent god of a fledgling tribe in Zion.
For an example from cut content since restored via mods, we have Meyers' speech to a group of reformed Powder Gangers if he's chosen as Primm's sheriff.
Sheriff Meyers: I know you all want redemption, and so do I. So let's go get it. Let's bring the law back to this town!
Cass' friendship with the Courier. When she's not a companion, her first line of dialogue is to sarcastically joke that you've come to take her back on the road because you missed her, incidentally making her the only companion (except possibly Boone) who inquires if you're looking to head out together without prompting. Furthermore the note when you sent her back says that she does so, albeit "reluctantly".
All companions in general display obvious fond attachment for the courier after completing their associated quests for upgrading perks, some almost to the extent of Undying Loyalty. It's an especially telling difference to Fallout 3's companions, who join based on morality. Meanwhile, Raul is obviously saddened if he's dismissed to his lonely shack, Veronica yearns for traveling with you even after resolving her quest, and even if you're not Lily's grandson she calls you a dearie. In gameplay mechanics, you can always re-recruit a companion, while in Fallout 3 you might've had to fulfill karma requirements.
After doing a makeshift detox cure for a mechanic (who will then work to maintain the Freeside water pump), a chemist (who will then make medicine for the Followers of the Apocalypse), outing a scam posing as an elite bodyguard, ease off the tensions between the Kings and the NCR... The followers offer you a dose of medicine per day, the King guarding the pump allows you to drink from it as much as you like, and every day, a random king will give you a gift (a few caps, some food...). I know I'm armed with an awesome suppressed sniper rifle, clad in an advanced stealth suit, packing enough food and water to last for 2 weeks, medicine for a rainy day, and enough ammo to depopulate a town and as such, I don't need any of these... But it's nice to see someone acknowledge and reward my good deeds.
Ulysses has more than a few of these, particularly during his time with Christine. The player meets Ulysses as a (possibly-insane) ex-Legion demagogue, who intends to bring back the Old World by any means necessary, by and large for the sake of Revenge upon the Courier. However, he fights his way through a small legion of robotic guards to break Christine out of the Auto-Doc that was torturing her, and is implied to have gently nursed her back to health before continuing with his mission to hunt down the Courier.
He gets another really clear-cut moment with this at the end of Lonesome Road, when he talks about the Courier. Even after all his bitterness about losing The Divide to the Courier, he says of the player character -