"When my journey began, I wanted only bloodshed, but along the way, when people saw me, they assumed I was a Jedi. And they needed my help. And... I gave it. I gave myself. It was right. It felt good. It was the only good thing I'd felt in so long."
Generally one of the main themes of the series Trigun, the only happy people are the good guys. This is best exemplified by Livio who is much happier protecting people than he was when he was a servant of the Eye of Micheal.
Digimon Tamers: Impmon realizes this after his Redemption Promotion. Patching things up with his tamers and joining the fight against the D-Reaper made him happier than he'd been all season.
In Fate Zero, Kiritsugu Emiya spent his entire life being a "hero" who Shot the Dog repeatedly and earned no real satisfaction from it. In the end, he found fulfillment and peace simply by rescuing and raising a little boy, Shirou, who was one of the only survivors of the cataclysmic fallout of Angra Mainyu's release during the fourth Grail War. In a way, Shirou saved Kiritsugu too.
The original run of the Thunderbolts!, who were a team of villains masquerading as heroes in the hero-starved post-Onslaught Marvel Universe. Baron Zemo's leading the whole team into gaining the trust of the public before really breaking their will... but most of the Thunderbolts really like being treated like heroes.
MACH-1 (the disguised Spider-Man villain The Beetle) is surprised to discover that, after he and Spider-Man have been Back To Back Bad Asses, he can not take a gift-wrapped opportunity to frame him for murder — a hero like MACH-1 would never do that.
MACH-1: This hero thing ... well, I'm starting to think it's contagious.
In an comics arc in the Star Wars Expanded Universe, after ex-mercenary DarcaNyl takes a dead Jedi's lightsaber and goes in pursuit of the Dark Jedi who killed his son, he is repeatedly mistaken for a Jedi by the people of various worlds. He is drawn into helping them, even at the cost of time he could have spent in pursuit, and in a textbook example, he finds that he likes it. "Lycan said to me, Men are not driven by altruism. I'll prove him wrong." In a later comic, though, he's bitter and isolationist again, because he tried to do good and be good and failed, because that's edgier.
In Pre-Crisis Superman comics, Lex Luthor uncharacteristically does a good deed that saves an alien civilization. The people are so grateful that they rename their planet Lexor and hail him as a hero. Lex is startled by how good it feels. In the following years, he marries a Lexorian woman and at one point even tries to go straight and settle down there. Unfortunately, it can't last. He just can't leave his evil past behind him, and a fight with Superman accidentally leads to the destruction of the entire planet, for which Luthor blames Superman and comes to hate him far more than he ever had before.
An unusual example comes in the form of PJ Maybe in Judge Dredd. He started out as a gleeful serial killer and identity thief, and at the end of the story, managed to become the mayor of Mega-City One. In order to keep up the farce, he had to do quite a lot of good work - and discovered he enjoyed it immensely, so much so that he now works to improve people's lives because he wants to. That said, he still loves to kill people, only now he tends to focus on the worst criminals.
Damien Wayne started out as a homicidal Jerkass thanks to being raised by the League of Assassins and spoiled rotten since birth. He later finds fighting the good fight as Robin to be far more fulfilling than being the heir of a new world order. When push comes to shove, he ultimately chooses the ideals of the Batman family over those of Ra's Al Ghul. He's still kind of a jerk though.
Batman himself started his career because saving other people from having to go through what he went through as a child made him feel better about his personal tragedy.
In the final act of Buck Godot: Zap Gun for Hire, the Beemahs - bio-engineered living weapons who are, essentially, energy-weapons with legs - are shown trust for the first time, by the titular Buck Godot. All of their past associates treated them like wild dogs, using them against enemies but always keeping them in check with some weapon or threat. They find that they LIKE being trusted and respected, and respond by being as good as their word - and then some.
In The Thing series, Nighthawk and Constrictor are among many trapped in Arcadia's Amusement Park of Doom. Nighthawk suggests that he and Constrictor, instead of fighting each other, work together to free the rest of Arcadia's prisoners. Constrictor is less open to the idea, since he's, y'know, a villain, but Nighthawk points out that he himself used to be a villaintoo.
Constrictor: I don't get it, Richmond. Why'd you switch over? Why risk your neck being a good guy?
Nighthawk: Well, I could give you a song-and-dance about doing the right thing. But in all honesty...I do it because it's fun!
Spider-Man always lives by the creed that "With Great Power Comes Great Responsibility". In one story someone asked him "What comes with great responsibility?" All Peter had to do was point to the rest of the city.
A subversion of this trope occurs in Teen Titans fanfic Adaptation. The Teen Tyrants switch bodies with the Teen Titans, pretending to be them to the general public. Ravager finds pretending to be a superhero surprisingly pleasant, but ultimately remains committed to being a villain upon his team's return to their own bodies.
Kin in the Naruto/TMNT crossover fic Teenage Jinchuriki Shinobi is much happier as a member of team seven in Konoha than as an agent of Orochimaru.
In Schindlers List, Schindler tries to pull this on Amon Goeth. Goeth gives it a shot and quickly decides that evil feels better.
In one Russian children story the main hero fights a clique of bullies led by an evil sorceress (yep). After one of the "villains" fails an operation, his mistress condemns him to a terrible punishment: within a day he must commit... THREE GOOD DEEDS. Naturally, his cronies are dumbfounded with such severity and the delinquent himself can barely brace himself to serve his term. But after the first deed he suddenly realises that doing good is not painful but pleasant, goes on a do-good spree and eventually defect from his gang.
In one of the Dragonlance stories, Palin Majere, nephew of Raistlin, wonders why he should become one of the "white robes", the good wizards. And why he just shouldn't choose whatever order makes him feel good. After he does a good deed, the head of the White Order mentions that he found that doing good does help himself.
Raistlin himself is some sort of subversion of this trope, since he saves people from threats and oppression several times but remains a very evil wizard. He says he just likes the idea of people owing him more than they can ever repay.
It's also a case of very specific empathy; having endured suspicion and hatred for all his life, he is always a friend to the downtrodden and abused, but despises the happy and content.
Happens occasionally in the Heralds of Valdemar series; When Skif, a thief, decides he'll be a good guy rather than returning to his thieving ways after being chosen as a Herald. Why? Because having a companion is just that awesome.
It should be noted that Skif was never really a bad guy to begin with, the legality of his chosen profession notwithstanding.
An aging, retired black-market weapons dealer in Dean Koontz's second Frankenstein novel finds this happening to him, because his four hired servants are devout Christians who know exactly what kind of man he used to be, and rather than hate or fear him, they dote on and care for him with love and respect. Now he sincerely donates to charities and orphanages and considers the moral consequences of his actions.
"It's amazing. They've all been so nice to me for no reason, and after a while I sort of wanted to be nice to them."
"It is. It really is."
This is what happens to pretty much the entire D'Haran army in the Sword of Truth series once Richard takes over. Several times it's mentioned that the soldiers feel good to be fighting for a good cause as opposed to conquest (though at first, a few are mentioned as missing the gains of looting and pillaging). As General Tiramac puts it, "it just feels better to have a wizard here who's more intent on putting the guts back to a man rather than have them taken away".
This was Socrates'/Plato's reasoning in The Republic for why we should behave morally - a truly good person has an ordered and balanced soul and is therefore better off no matter what the external circumstances. Aristotle put a few not-so-subtle Take Thats in Nichomachean Ethics against the idea that a good person impaled on a spike is happier than a bad one surrounded by wine, women and song.
"To hold dear the effort more than the prize may be called love. The joy of doing something not for the prize one would get in the end, but for the joy itself, that may be called love. To do good not because you are going to be rewarded for it in this life or in a life to come, but to do good because you enjoy doing good, that is to love good. Love is its own reward. Love makes all things possible. Love offers peace. When love is at stake, my children, yield not to an army."
One thing Lara understood was the expressions turned on her. They were the eyes of a group to whom she belonged. Not since her parents' loss had she seen that expression.
A reversal - Evil Feels Terrible, if you will - appears in the novel Death Star. The gunner who fired the superlaser that destroyed Alderaan, who had always wanted to fire the biggest gun, finds that following orders and actually getting what he'd wished for led to misery beyond his wildest dreams, a personal Moral Event Horizon. Unlike a lot of other doers of evil deeds, he can't justify it, can't either make it less of a crime or blame someone else, and is unable to sleep. When the Death Star is in range of Yavin he stalls desperately, hoping that something would happen and he wouldn't have to pull that trigger again. He got that wish, poor bastard.
In Allegiance, the five stormtroopers of the Hand of Judgment, on the run after their leader refused to kill unarmed civilians and then killed an officer in self-defense, find themselves still trying to follow the oath they swore to protect citizens of the Empire. They end up doing things like saving farmers from swoop gangs, taking out a corrupt security chief to get previous security people back in place, getting a man preparing to violently secede arrested, and very reluctantly helping Han Solo and Luke Skywalker and Leia Organa, although it probably helped that they thought those three were "normal" Rebels. At the end of the novel, Mara Jade saves them and tells them to keep their heads down, but when she leaves, they don't see how they can.
La Rone: "We swore an oath to defend the people of the Empire. There are a lot of other dangers out there they need defending against."
Brightwater: "Actually, I was kind of hoping you'd say that. For all the bumps and bruises, this hero stuff definitely helps you sleep better at night."
The Force, in general, is supposed to feel like this. A particularly nice description can be found in I, Jedi:
Streen: "It feels like ten kilos of life in a five-kilo box. I can only feel a trickle now, like dust motes floating in a sunbeam, one by one, just moving through me, but it's just so right there's no describing it. It tickles a bit, feels like a first kiss, or the jolt you feel when the flux in sabacc just makes your hand better than what you were already betting."
A few pages on Corran, who'd asked Streen about it, opens himself fully to the Force for the first time.
It filled me up in an instant and I imagined it leaking from my eyes, nose and mouth. I wanted to shout and dance with joy because it was everything Streen had described. It was what I felt when Mirax first said she loved me. It was the scent of the perfume my mother wore, and the warm laugh my father used to have when he was proud of me. It was the hearty slap on the back from Wedge after a mission and even a touch of Whistler's triumphant serenades. It was everything that was good and right and positive and alive; and it was waiting for me to bend it to my will.
Moist von Lipwig in the Discworld books, specifically the end of Going Postal. Well, sort of: he's been running on adrenaline and dancing on the edge of collapse and loving the hell out of it for so long that he can't go back to being a simple confidence trickster; it would just be comparatively unexciting.
played with in the sequel, Making Money. Moist's job has become boring and his mood has deteriorated to the point where he is breaking into his own building because he can, and even carrying around a blackjack despite the fact the he loathes weapons. He starts acting heroically again after being tricked and coerced into a new job as the head of a bank. Seems that Moist would rather be a bad guy with an interesting life than a good guy with a boring one, but being a good guy with an interesting life is even better.
In The Stand, Harold is The Resenter, and decides to help out the good citizens of Boulder just so that they won't suspect he's The Mole. While doing so, he discovers that the good guys genuinely appreciate his help, and wonders if maybe he should just try Becoming the Mask. The usual Heel-Face Turn, however, is subverted when the Dark Side offers him really mildly kinky sex.
After his Heel-Face Turn, Skeeter Jackson of Time Scout enjoys trying to be good. He really enjoys it when he gets to use his old skills to do good deeds.
A Song of Ice and Fire, despite being a Crapsack World extraordinaire, has an unexpected instance of this in JaimeLannister. He discovers, much to his own surprise, that he quite likes the feeling he gets from enforcing justice, protecting the helpless, keeping his word and preventing massive bloodshed. Inevitably, he is forced to Kick the Dog again before long, but (assuming he survives much longer) things are actually looking very hopeful for his further moral development.
In the prison drama Oz, there's an episode where all of the inmates collect money to send inmate Bob Redabow's grandson to Disney Land before he dies of leukemia. Another inmate tries to talk Simon Adebisi, one of the most dangerous and vicious inmates in Oz, into robbing the old man of the money. He refuses, and says "'Cause sometimes it's good to be human."
In Buffy the Vampire Slayer, Faith's HeelFaithTurn immediately follows an event where she switches bodies with Buffy. And in doing so she becomes Buffy (or rather, her idea of what Buffy is like. She adopts what she thinks of as Buffy's Catch Phrase: "Because it's wrong"). Notice how Buffy is in no way affected by being in Faith's body. Bear in mind that Faith knows what is going on before it happens, and wants to stay "in disguise" long enough to make good use of it. Hence her attempt to act like Buffy, complete with practice session. After that, it's Becoming the Mask.
Even a soulless vampire, Harmony, is very briefly affected by this when she tries to join up with Angel's team. Regrettably, she finds that vampire cultists are much better at accepting her for the vicious killer she is.
The second episode of Leverage does this, the Five-Man Band begrudgingly steals a few million dollars knowing they'll have to give it back, but they feel a bit better once they see the reaction of the injured veterans to the money that can be used for rehab.
Also explained as the reason for the second season premiere; while everybody had broken up at the end of the first season, they came together and agreed that they couldn't just go back to lives of crime, and that they wanted to keep being heroes.
Strictly speaking they are still leading lives of crime. It's just that it's good-guy crime.
In a NewsRadio episode, Dave and Bill are stuck in an airport in the Midwest. Bill begins mockingly acting as friendly as the locals, but eventually starts to forget he was being sarcastic, and it starts to feel good. "Do you mean this is how you feel all the time?" he asks Dave. "Except for when I talk to you," Dave admits.
Gaius Baltar of Battlestar Galactica is just about the most selfish and narcissistic person there has been, though he has improved considerably from how he used to be even, and after undertaking a series of charitable acts mostly out of a desire to regain standing, discovers that it actually made him feel good to do good.
Possibly the entire point of My Name Is Earl, Earl starts doing good things for fairly selfish reasons (he wants good stuff to just happen to him) but fairly quickly finds out that Good Feels Good and starts trying to do the right thing for its own sake.
Xena started out as The Atoner and then morphed into this. By the middle of first season, she's talking about doing good like it's heroin.
As of the fifth volume finale of Heroes, a freshly-turned Sylar seems to have finally settled on this — subduing Eric Doyle and tying him up for the police really did feel better than going the extra mile and killing him.
In Kamen Rider Den-O, Momotaros originally wanted to cause havok like all Imagin. Then he came found out that being good meant he got to fight...a lot. Clearly for a battle hungry Imagin like him, this makes being good really fun.
This is actually used by House to justify his indestructible misanthropy; because Good Feels Good, people only do good to feel better about themselves and not out of real moral convictions.
In the season 4 finale of Charmed, this is the reason why the main characters don't give up their powers when the Angel of Destiny offers them a normal life.
Paige: We saved someone. It felt good. It felt... right.
This was part of the reason why Kyra the Seer wanted to abandon the Underworld and become human; the other part was because the Avatars intended to wipe out demons to create their World of Silence.
Former Jerk Jock Shun Daimonji decides to help out the Kamen Rider Club in Kamen Rider Fourze even though Gentaro notes that he's not going to get recognition for his efforts, but he'll know that he's doing something good. Shun's fine with that.
In one episode of the Korean Banjun Drama, a conman hired a single mother and her son to pretend to be his family, in order to fool a cop who had been chasing him for years into thinking that he has reformed. By the end of the episode, however, the conman does truly start to care for his "family" and chooses to put his past life behind him and become a good father and husband.
Person of Interest: Fusco complains that he was just getting used to being a good guy when Reese insists he go undercover with HR.
An example from the last episode of Tomica Hero Rescue Force shortly before they run out of power, Maare, Saan and Shica grab from the corridor and ask him to save Maen It's not, everyone's just under the effect of a Scarecrow-style Fear Gas. Just before they're completely drained the three of them realise that "Saving lives ... isn't so bad after all,"
It's revealed in the epilogue that the three of them join Rescue Force as repairmen and a Meido
In Beetleborgs, the heroes eventually managed to steal the Astral Axe from the villains, and summon Boron in order to use him against the titanic monster Repgillian. While it eventually took more than Boron to defeat it, once they did defeat it, Boron decided that he liked fighting for the side of Good better than what he was doing before.
This is a major theme in Pink Floyd's music, especially The Dark Side of the Moon, Animals, and The Wall, all of which describe what happens when the trope doesn't come into play. "Pigs on the Wing (Part 2)" flat-out says it:
You know that I care what happens to you
And I know that you care for me too
Now I don't feel alone or the weight of the stone
Now that I've found somewhere safe to bury my bone
Avenue Q has an entire song about this. (The Money Song). Somewhat subverted in that the reason why the characters are doing good deeds is to get things for themselves. Princeton wants to start a Monster School (which he thinks is a stupid idea) so Kate will be so happy that she'll take him back; Nicky wants to find Rod a boyfriend so he'll let him live with him again. As the chorus goes, "When you help others/You can't help helping yourself/Every time you do good deeds/You're also serving your own needs/When you help others/You're really helping yourself."
Parodied in one Sunday strip of Dilbert. Dilbert offhandedly mentions that he donated a few hundred dollars to charity. Dogbert gets fired up and mocks Dilberts supposed altruism, claiming that he only did it to make himself feel better. Dilbert agrees, saying he feels pretty good. Dilbert then asks how much Dogbert donated, and Dogbert admits he donated a thousand dollars, which is why he's so torqued.
Occurs in Warhammerof all places. A particularly detested Elector Count was challenged to a duel by a wandering Champion of Chaos. The Count was defeated, to which the womenfolk started cheering wildly. Feeling obscurely pleased, the Champion left the town unscathed.
The big point of Dead Inside. The game was designed to, in the creator's words, invert the "kill people and take their stuff" behavior of other RPGs to "heal people and give them stuff." The feeling of gaining a new soul point is like a rush of warmth and energy, one that can make a person dizzy and excited from the experience. Good literally feels good.
The Dungeons & Dragons Splat book The Book of Exalted Deeds includes an Exalted Spell (as in, a spell only usable by Exalted characters, the purest followers of Good) called Vision of Heaven, which shows someone a brief glance of Mount Celestia, the afterlife of virtuous soul. If shown to an evil person on a regular basis (along with other forms of therapy) these visions can aid in attempts to redeem the character (there's a whole chapter dedicated to this in the book). The idea is, basically, to show him what sinners ultimately are denied; it can work wonders.
In The Lion in Winter by James Goldman, King Henry II talks about the frequent wars between England and France during the Middle Ages:
"Since Louis died, while Philip grew, I've had no France to fight. And in that time, I've discovered how good it is to write a law, or make a tax more fair, or sit in judgment to decide which peasant gets a cow. There is, I tell you, nothing more important in this world. And now the French boy's old enough, and I am sick of war."
Trauma Center, you can't go wrong when a game lets you play as a surgeon!
Rather interestingly done in Metal Gear Solid, after beating Psycho Mantis - during his Final Speech he reveals a secret passage (and apparently implanted the locations of claymores in the next area in Meryl's head), and quietly admits it "feels nice to help someone else for once" before dying.
In Baldur's Gate II: Throne Of Bhaal, you can get your evil brother and former Big Bad Sarevok to join your team. While he's utterly evil, you may, through proper dialogue choices and much showing of genuine respect and decency, convert him to the cause of good for real. After which he does admit that indeed, Good Feels Good.
Knights of the Old Republic allows a Light Side player several opportunities to reform Dark Jedi he encounters back to the Light Side via a healthy mixture of kind words and some gentle slaps with his lightsaber. This earns you allies as well as a chance to give a huge Take That to all the Sith gibberish of a philosophy. Arguably the best instance of the trope is when you and one particularly asshole Sith-wannabe are both captured by an insane old Sith and are subjected to a torture/quiz in "Better you than me" style (you answer wrong - you suffer, you answer right - HE suffers). If you are persistent enough in wrong answers, he is eventually released and is free to go, essentially leaving you to your doom. In a Crowning Moment of Awesome he instead uses Force to release and revitalize you, and together you proceed to slash the shit out of the old crook. BUT WAIT, It gets better! Although you cannot talk the Big Bad out of the fight, still after you defeat him, he repents. Kind of.
This certainly is the basis of Super Robot Wars Advance. Your character is sent as a spy from an evil organization, melding with the good guys, thus having to act good, in Lamia's case, or just plain forgot the evil part and got swept up with doing good, in Axel's case. When it comes to betraying the good guys just as planned... Good feels better than Evil, so they end up having their official Heel-Face Turn.
Spike notes this when you destroy the machine that covers Flower Fields with clouds.
In Paper Mario: The Thousand-Year Door, poor Vivian was clearly in a situation where Being Evil Sucks. As one of the Shadow Sirens, her sisters treated her like garbage, and always dumped the blame for their mistakes on her. Then, as fate would have it, she met Mario, and because he couldn't tell her his name due to Doopliss' spell, the two formed a brief partnership, and for the first time in her life, someone was treating her decently. When she did find out who he was, the choice was between staying with someone who was treating her nicely or going back to two rotten sisters who were treating her like dirt. What other choice could she make?
In Jade Empire, you can encounter a mummified noble who is destined to be unable to return to the wheel of life due to the depravity he was known for in life. If you convince him to donate his liver to save a dying little girl, his spirit appears once she is saved and tells you that he has learned that Good Feels Good and that because he has learned this lesson, his spirit will be allowed to pass on (once the problem that has trapped all ghosts in the mortal realm is solved, that is).
While Zevran of Dragon Age: Origins never really gets out of the "assassin" mindset unless he is romanced, he will (at a high enough approval rating) admit that helping the Grey Warden to stop the Blight and save Ferelden is the best thing he has ever done with his life.
While preparing to defend Redcliffe from a Zombie Apocalypse, it's possible to convince the greedy and selfish bartender Lloyd to join the fight. If he survives (which he might not considering he has no armor and only wields a dagger), he mentions that it felt good to help and will offer you a magic ring in thanks for sending him out since his fellow villagers respect him now.
Mass Effect is well-known for encouraging this in players. In the second one, you get emails from people you help, including people you helped back in the first game, just to give players the warm and fuzzies.
Subverted when you receive a heart-felt "thank you" from a serial killer you inadvertently helped escape, which he hastily ends so he can go and greet his next victims. Oops.
There's also the Paragon/Renegade scars in Mass Effect 2. If you consistently make Paragon decisions, your facial scars will slowly fade. If you make Renegade decisions, they will slowly get worse.
If you earned Good Karma by the first Train Mission in inFAMOUS, the people who initially blamed Cole for the blast and referred to him as a terrorist cheer for saving all the people. Cole calls them hypocrites, but admits that that the good he did made him feel good.
In Dominic Deegan, after Jacob saves Luna from a possible Fate Worse than Death, he realizes that he has been wrong about... basically everything and decides that he should remake himself and his life.
Belkar in The Order of the Stickrealized that "I can do exactly what I always do-murder people horribly-but because I killed the people everybody else wanted me to kill, I get presents instead of prison time." The group is slightly worried about this.
In The Salvation War a demon herald Memnon, after his defection to humans, contemplates on how nice it feels to have superiors who care about him, appreciate his abilities and praise him for his achievements instead of constant cavils, threats and general neglect he received from his masters in Hell.
Similarly, "Drippy" in the later books feels the same way— the camaraderie between him and his squadmates, especially once he realizes they've accepted him as one of their own, makes him feel better than anything he had back in hell.
Smithers: It feels good to be helping people, doesn't it, sir?
Mr Burns: No. It feels weird.
In one episode of The Snorks a two headed monster (one head was good, the other bad) was the antagonist. Then one of the cast nearly got trapped in a dangerous situation, and the two-headed monster saved her, though the bad head didn't seem to realize this. After receiving gratitude from everybody else the bad head realized that it liked the way helping other people made it feel and stopped being bad.
After his Heel-Face Turn, it didn't take Tohru long to decide he liked helping people a lot more than being a Dark Hand thug. (One reason he did so initially was - aside from almost getting killed when Valmont told him to fight Shendu - was because Section 13 "serves donuts every Thursday". All jokes aside, however, he really told Valmont off when the criminal came to the heroes for help, telling him that Uncle was a far better boss than he ever was.)
Discord figures this out once he's released by Princess Celestia and the main characters and is accepted by Fluttershy as one of her friends.
This is the core of Pinkie Pie's character. Her Smile song exemplifies her ethos quite well.
From a logical perspective, empathy is a large reason (though far from the only one) for the existence of this. Empathizing with the people you help allows you to imagine the relief, appreciation, comfort, etc. of the people that you help when they receive it. When empathy becomes an internalized mindset and behavior, helping people (or just doing good deeds) becomes so natural and desired that one won't even consciously think about why he/she does it, unless he/she has to explain it to others.
Ashoka, an ancient emperor of much of India, was originally a conqueror, waging wars that killed hundreds upon thousands. That was, until, all the dust settled, and he realized he felt really, really, bad. He then converted to Buddhism, became a vegetarian, and spent the rest of his life striving to improve the lives of his subjects and spreading Buddhist teachings.
If this were not Truth in Television, pretty much every charitable institution that either A) relies on volunteers or B) relies on donations would cease to be.
Subverted in some cases, in that self-righteousness (ranting, raving, etc) is also a natural high.
Four words: Random Acts of Kindness.
Emanuel Kant posited that an act of pure utilitarianism (the greatest good for the greatest number of people) should not depend on any kind of reward - you should do good because good is good. If you derive any gain from your act of kindness - monetary gain, preferential treatment, basic gratitude or even a feeling of satisfaction, then you are acting on gain, not pure goodness. Consider how many people would actually want to adhere to such exacting standards.
Also consider that it completely falls victim to Moving the Goalposts; someone who hates the poor and charity can give to charity and quality under Kant's philosophy, but someone who loves helping the masses and disadvantaged does not qualify by dedicating her/his life to helping the poor, at the expense of a more comfortable living style, higher income, etc. Regardless, Kant fails to realize that empathy prevents someone from qualifying, as going good unto people you hate/cannot empathize with whatsoever is the only way to qualify.
This trope is likely the motivation behind the creation of open-source software. The authors don't expect to get anything for their efforts, but other people (who may not have their coding skills) find their software useful. Knowing your software has helped someone out must make you feel good.
This seems to the ultimate point of thisCracked article by David Wong. Trying to increase your own happiness by seeking power in all its forms will only make you miserable. Real happiness can be obtained, paradoxically enough, simply by helping others while not thinking too much about our own happiness.
Discussed a lot by Doug Walker, who realizes that some consider him a Extreme Doormat for the way he acts, but doesn't care because he just really likes being nice.