->'''Hiroim''': Impossible... \\
'''Caiera''': He shifted the very plates... \\
'''Korg''': Of course he did, he's the Hulk. \\
'''Caiera''': But you said he couldn't. \\
'''Korg''': I was just making him mad. He seems to work best that way.
-->--''PlanetHulk''

Our hero has acquired a new onboard superpower through the power of an origin story or receiving AppliedPhlebotinum. Unfortunately, the effectiveness of the power or device depends on the mental stability and/or confidence of the user. Inherent to TheDarkSide.

Naturally, tends to be an example of PersonalityPowers. Not to be confused with PsychicPowers or [[PsychoSerum powers from psychoactives]]. Compare HeroicSpirit and ThePowerOfLove, which may overlap with this trope.

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!!Examples:

[[AC:{{Anime}}]]
* ''TengenToppaGurrenLagann''. The mecha of the series, called Gunmen, are powered by Spiral Energy, which comes from living things. The amount of Spiral Energy one produces is tied directly to their emotional state. Fear and despair lower it, hope and optimism increase it, and [[HotBlooded Hot Blood]] blasts it to OverNineThousand.
* ''LightNovel/HaruhiSuzumiya'' fits here. Of course, Haruhi ''doesn't know''. It specifically depends on mental ''instability'', and the rest of the cast spends a great deal of effort ''preventing'' this.
* ''Anime/NeonGenesisEvangelion''
** Specifically, synchronisation strongly depends on the part of the brain associated with certain emotions, such as those between two lovers, '''or the love of a parent and child''', hence all the {{Soul Jar}}s and MommyIssues orchestrated by NERV
* The Lambda Drivers that power the HumongousMecha in ''LightNovel/FullMetalPanic'' work like this. The {{technobabble}} basically stated that it runs on AppliedPhlebotinum that begins generating energy when exposed to brain waves above a certain level, which are reached when the brain is processing especially intense emotion.
** The bad guys found a way around this, by using a drug to keep their Lambda operators at peak emotion at all times. [[AxCrazy Has some side effects]].
* Orihime's abilities in ''Manga/{{Bleach}}'' are restricted by her willpower. Her powers could be very powerful offensively [[spoiler: she wields them by ''[[RealityWarper willingly rejecting reality]]'']] if she actually ''wanted'' to hurt anyone, but she's an ActualPacifist, and so generally only uses them for [[TheMedic healing]] or [[BarrierWarrior defense.]]
* The [[{{Hammerspace}} N.O. portal]] connecting [[MegaCorp Medica Mechanica]] to [[Anime/{{FLCL}} Naota's head]] seems to get wider during times of emotional distress.
* In ''YuYuHakusho'', Kuwabara is undoubtably the weakest of the heroes, but has proven capable of [[UnstoppableRage short bursts of incredible power]] when [[RoaringRampageOfRevenge properly]] [[LastStand motivated]]/[[ThePowerOfLove inspired]].
* Soul wavelengths in ''Manga/{{Soul Eater}}''. Mindset affects both the powerful moves that require a high level of soul resonance between meister and Weapon, and the basic ability of the two to work together.
* Goku of ''Franchise/DragonBall''. When the chips are down, he'll take a beating and be on the ground battered and bruised -- but ThePowerOfLove is Goku's secret weapon. Remind him his loved ones will suffer if he doesn't get back up, and he'll find hidden reserves of strength and deliver a curb stomp to the bad guys.
** It's true of his son Gohan even from childhood. As a small boy, his power level is pathetic when he's scared but when he's angry it climbs and keeps climbing, enough to nearly knock a full blood Saiyan off his feet.
* The I-field barriers used by the [=SUMOs=] in ''Anime/TurnAGundam'' are said to operate at least partially on the pilot's willpower (which goes a long way to explaining why [[HotBlooded Harry Ord's is so strong]]). The Moonlight Butterfly will also only manifest when the pilot has the proper amount of determination to activate it.
* The ''[[Anime/MobileSuitGundamUnicorn Gundam Unicorn]]'''s NT-D system only activates when the pilot is under a certain amount of emotional stress[[note]]A Newtype must also be present on the battlefield[[/note]]... typically anger or fear (common battlefield emotions), but Banagher manages to activate it in episode 4 through determination to help someone. Later on he seems to be able to activate it at will discarding all previous limitations on the system.
* Before the I-Field and the NT-D, there was the Bio-sensor of ''Anime/MobileSuitZetaGundam'' and ''Anime/MobileSuitGundamZZ'', which were miniature psycommu systems that were meant to just make the suits easier to control. Instead, they ended up making the machine's stronger through their pilot's anger. For Kamille Bidan, he made the Zeta powerful enough to turn a beam saber into a massive beam whip, then gathered the ''souls of the dead'' to fuel a kamikaze attack! For Judau Ashta, he was able to recombine the Double Zeta and super charge its Hi-Mega Cannon to the point where it actually melted the V-fins on the head.
* Dragon Slayer powers work this way in ''Manga/FairyTail''. [[TheSmartGuy Happy]] actually revs [[HotBlooded Natsu]] up into beating a BigBad by suggesting he should back off and let [[TheRival Gray]] handle it.
* ChaosHead has the Di-Swords, only functional through... [[PowerBornOfMadness delusions.]] Thus, in somewhat of a departure from the classics, the user ''has'' to be screwed up in order to use the weapons. This, though, [[MindScrew is only fitting]] in a show such as ChaosHead.
* That's how the power of a Manga/{{Pretear}} works. The Pretear has the ability to create LifeEnergy, but her abilities may fail her if she loses the will to fight... and if she gives in to her dark side, her power can reverse completely, turning her into someone who [[VampiricDraining absorbs life energy]] instead of generating it.
* While the powers in ''Manga/{{Psyren}}'' are mostly concentration/instinct-based PsychicPowers, there ''is'' emotion-fueled Psy... which are as [[HeroicRROD dangerous and unstable]] as they are powerful. The key to normal psy is concentration, [[ImaginationBasedSuperpower imagination]], and careful control over your energy; emotion-based powers are prone to running rampant and over-stressing their users. The only other known user of the protagonist's [[SphereOfDestruction psy]] died slowly from it degrading his health, and [[DyingAlone alone]] because his increasing distress made it manifest more often, which in turn [[Catch22Dilemma distressed him further and made his health degrade even more]].

[[AC: ComicBooks]]
* ''Comicbook/{{Empowered}}'': Emp's theory about her suit being shredded easily because her self confidence and self esteem are easly shredded is ''entirely accurate''. When she's not thinking about ending up in DistressedDamsel territory, she can make really effective use of the suit. [[spoiler: It has recently been confirmed that Emp's powers can be shut down by someone making her ''think'' about being tied up.]]
* The GreenLanternRing - if the user doesn't have a strong will, getting the thing to so much as light up is a herculean task. If the user has a decent will, they'll be able to create constructs, but they won't hold up well in battle when the user is frightened or rattled. If the user doesn't have much of an imagination, it forms very boring and mundane things.
** And now there's a whole spectrum of colors that require feeling or inspiring a specific emotion (rage, greed, fear, will, hope, compassion, love) in order to work. Though the compassion rings tend to get around this little caveat by [[spoiler: forcing their wearers to feel nothing but compassion.]]
* As of the ''Comicbook/CaptainBritainAndMI13'' series, Captain Britain's powers work like this; super strength and durability in proportion to his confidence and emotional stability.
** His alternate universe teenage counterpart Kid Briton introduced in ''ComicBook/AvengersArena'' has the same powers which he fuels by being TheBully at the Braddock Academy.
* Gladiator, AKA Kallark, of the MarvelUniverse, is like this; his power is based on his confidence. This spirals both ways; being the [[SuperpowerLottery most powerful mortal in the universe]] when he's on top of his game, he's ever-more-confident when things are going his way- but when something finally does go wrong for him, the shock can make his power collapse ''quick.''
* {{Spider-Man}}'s powers have stopped working several times due to emotional issues, in almost every medium that he's been in. He gets them back when he becomes self assured again, usually just in the nick of time. Inversely, [[HeroicResolve when people he cares about are in danger his powers grow exponentially stronger]].
* Comicbook/TheIncredibleHulk. Bruce Banner only turns into the Hulk when angry, and then [[CatchPhrase the angrier Hulk gets, the stronger Hulk gets]].
** This does [[DependingOnTheWriter depend on the writer]]; sometimes the Hulk's transformations are portrayed as the result of adrenaline, both in the form of anger and excitement or fear, other times it is portrayed as a pure survival mechanism, activating to save Banner's life regardless of emotional state. But the anger fueling strength connection is generally maintained.
* [[SheHulk She-Hulk]] (Jen Walters, that is) can usually use her powers at will, but she has been stuck before in her Hulk form due to subconscious unwillingness to change back, and in her human form when she was too scared to become She Hulk again. If you make her angry enough, she can also turn into a Savage She Hulk that is very reminiscent of he cousin's form.
* Comicbook/{{Superman}} once lost his powers for a year, then got them back when he cheered up and enjoyed his life.
* In ''{{Marvel}}'' the superhero Speedball, after becoming [[DarkerAndEdgier Penance]], found that his [[DiscardAndDraw new powers]] only worked when he was in pain. Cue the iron maiden styled combat suit. Except, WarrenEllis [[{{Thunderbolts}} realized]] that people who cut themselves process pain abnormally; the adrenaline rush of self-mutilation triggers an endorphin reaction, in effect making them ''high''. Thus, his powers have the same trigger as always; he can't use them unless he's happy. As the FunPersonified character he had been before ComicBook/CivilWar, it makes some sense that this had previously not been noticed. Doc Samson points this out, and in the process helps him start overcoming his depression.

[[AC: FanFic]]
* Chapter 5 of ''FanFic/SaviorOfDemons'' reveals that [[PoisonousPerson Frieza]], and all Arcosians, have a very mild venom [[PsychoactivePowers that only activates when they're terrified]], which becomes a plot point because it paralyzes Goku's right hand...meaning that he can't use Shunkan Idou until it's treated.
* The Self-Insert Orange Lantern's power in ''FanFic/WithThisRing'' is dependent on much Avarice he feels: meaning it gets more powerful the more he wants something or how it can benefit him. If it doesn't benefit him or he only wants to help, the ring won't work. If he doesn't want it or outright hates it, he risks the ring destroying it.

[[AC:{{Film}}]]
* Will Stronghold of ''SkyHigh'' was in the gawky, awkward stage of adolescence, and had no confidence. He also had no powers, but hadn't made the connection between the two. The fear and shame involved in the idea of disappointing his superhero parents also didn't help. But when Warren put his friends in danger, Will grew confident and his powers suddenly manifested in the middle of the fight.
* The male lead in ''My Demon Lover'' only transformed into his formidable demonic aspect when he was ''horny'' enough.
* In ''Film/InTheNameOfTheKing: A Dungeon Siege Tale'', the BigBad Gallean goes mad with power and gains abilities not normally available to the magi. During his magical duel with Merick, this is the only thing that allows him to surprise and defeat the more experienced magus.
* ''Film/XMen'':
** In ''Film/XMen'', in a blink and you'll miss it moment: Storm is knocked down an elevator shaft. She rises out of it flying with her trademark all white eyes, and delivers her line to the Toad about what happens when a toad gets struck by lightning. This is an obscure reference to the fact that in the comics, Storm is extremely claustrophobic, and the ensuing panic that causes often amplifies her powers beyond normal levels.
** In ''Film/XMenFirstClass'', Erik's control of his abilities is directly linked to his emotions.
** In ''Film/XMenDaysOfFuturePast'', Charles can't control Cerebro until he [[spoiler:gets some advice and encouragement from his future self]] and stabilizes emotionally, after which he's fine.

[[AC:{{Literature}}]]
* One of the stories in the Azazel series by Creator/IsaacAsimov involves an [[HollywoodAtheist irritating atheist]] given a {{Jetpack}} and told that it's powered by his belief in science and logic. The problem is, [[spoiler:those who see him flying call it a miracle, and convince him it's one too, making him incapable of using it again.]]
* Skeeve in ''Another Fine Myth'' must stop drawing upon his parents' or mentor's strengths for his confidence, and find it in himself instead, to finally light a candle with his magic.
* ''WildCards'': The school of thought that Aces are internally confident and end up being beautiful and powerful, while Jokers have some sort of internal self-hatred that manifests outwardly. This also reflects in their powers, because some Jokers have powers that would make them Aces if they weren't so hideously deformed.
* The wizards in ''Literature/{{Discworld}}'' are like this.
* Nynaeve in ''Literature/TheWheelOfTime'' can only use her magic when she's angry. [[spoiler: she gets better.]]
* In ''Literature/TheDresdenFiles'', Harry's magic is partially based on emotion. On several occasions, he has gotten ''very'' angry and used it to amplify his fire magic. On another occasion, he has used a surge of lust induced by a White Court vampire to power a shield spell.
** He has also stated that sometimes ''color'' can become part of the spell, as seen in ''Proven Guilty'' when he builds the net to find the phobophages. There's black for vengeance, white for purity, etc. When building the net, he uses blue play-dough because of blue's connotations with defense. Plus, [[PerpetualPoverty blue is cheaper]]. It is noted that the actual color isn't important- what helps is the mental associations the individual has with it. Because Harry was taught to use blue for defense, and has had past success that mentally associated blue and defense, it works best in that role for him.
* In Larry Niven's KnownSpace universe, this is how Gil "The Arm" Hamilton got his power and nickname. He had lost his right arm in an accident, but one day when he absent-mindedly tried to catch a dropped object with the missing arm, he manifested an "imaginary" psychic arm that works via telekinesis. One story notes that psychic abilities work only [[ClapYourHandsIfYouBelieve because the user believes in them]].
** It should be mentioned that while Gil's arm can handle hazardous materials and reach through solid objects [[PortalPicture or live video feeds]], it is otherwise limited to the same range as his flesh-and-blood arm (arm's reach), and only strong enough to lift a pound or two in Earth's gravity. People have asked Gil why he doesn't try hypnotherapy to correct these shortcomings; he points out that feeling like he has an arm ten feet long might interfere with his WillingSuspensionOfDisbelief and make his arm go away entirely.
* Three of the six main student wizards in ''[[DarkLordOfDerkholm Year of the Griffin]]'' have a particular quirk to their magic due to psychological issues:
** Lukin creates a pit of some kind whenever he tries to do anything with magic. Even his magefire appears in a little hole in his desk. [[spoiler: This turns out to be symbolic of the emotional gap between his father and the rest of his family, which his father refuses to acknowledge]].
** Olga used to be able to summon winds instead of monsters [[spoiler: by talking to [[ElementalEmbodiment air elementals]] that no one else could see. Her talents got twisted up when she refused to let herself cry and stayed that way for years, but the minute she tears up the elementals are back to comfort her]].
** Claudia's magic always seems to go wrong somehow, which she believes is due to a jinx.[[spoiler: it's actually because she has a strong gift for [[TeleportersAndTransporters translocation]], and she ''hates'' travel because [[HalfBreedDiscrimination she feels like an outcast wherever she goes]]]].

[[AC:LiveActionTV]]
* ''{{Chuck}}'''s Intersect 2.0 flashes only when he is calm enough.
* In ''Series/{{Haven}}'', a person's Trouble first activates when they get stressed or upset.
* In ''Series/{{Misfits}}'', Curtis can only use his MentalTimeTravel when he feels intense regret.

[[AC:{{VideoGames}}]]
* The central gameplay mechanic of ''VideoGame/SuperPrincessPeach'' is activating one of four "Vibes", which are abilities based on four emotions. In Joy, she gets the ability to float. In Rage, she gets [[ManOnFire surrounded by fire]] and gets a ShockwaveStomp. In Gloom, she gets OcularGushers that spray SwissArmyTears. In Calm, she heals herself.

[[AC:{{WebComics}}]]
* Zimmy from ''Webcomic/GunnerkriggCourt'' has some kind of PsychicPower (her exact abilities are rather vague so far). She also has a mental disorder--she describes it like having static in her head. The worse the static gets, the less control she has to prevent her powers from acting up.
* ''Webcomic/ElGoonishShive'': [[spoiler:Grace]] has {{telekinesis}} just strong enough to "arm-wrestle". But when someone makes her explode (figuratively), something may explode (literally).

[[AC:{{WebOriginal}}]]
* In ''Literature/{{Brennus}}'', some [[DifferentlyPoweredIndividual metahumans']] powers grow in strength as they approach the mindset they had during their TraumaticSuperpowerAwakening.

[[AC:{{WesternAnimation}}]]
* Presto from ''WesternAnimation/DungeonsAndDragons'' had this problem. No confidence in his abilities, so his magic worked sporadically, and rarely as intended.
* In one episode of ''WesternAnimation/DannyPhantom'', he temporarily gains the ability to control the weather, but it's based on his emotions instead of consciously controlled.
** This also applies to his general ghost powers during the beginning when it was more sensitive to his growing emotions.
* In ''WesternAnimation/TeenTitans'', Toonverse Starfire's powers are apparently triggered and/or powered by specific emotions, e.g., joy for flight, rage for {{Eye Beam}}s etc. [[RuleOfFunny Naturally]] this little factoid first cropped up when she got [[FreakyFridayFlip bodyswapped]] with [[EmotionlessGirl Raven]], whose powers [[PowerIncontinence go haywire]] without tight emotional control. It comes up again later, when Starfire finds herself unable to fly because she's confused as to the [[UnresolvedSexualTension status]] of [[WillTheyOrWontThey her relationship with Robin]].
* Rex's powers from ''GeneratorRex'' require him to be focused and level headed when using them. If he loses his concentration, for instance if he becomes confused his powers will fail.
* Bending works this way in ''WesternAnimation/AvatarTheLastAirbender''. Aang has to adjust his mindset when he learns a new element, which becomes a serious problem with the [[ThePollyanna happy-go-lucky hero]] has to learn to be steadfast and forceful to learn Earthbending. Zuko also loses most of the power behind his [[PlayingWithFire Firebending]] when [[spoiler: he joins the good guys and loses the hatred in his heart. Luckily, he finds a secret society where he learns that Firebending is about passion, not anger.]]
* In the episode of ''WesternAnimation/AdventureTime'', "Little Dude", The Ancient Sleeping Magi of Life Giving has life-giving powers that are dependent on his mood. When he thinks of his father, who it's implied never loved him, the objects he animates turn evil, but when he thinks of his mother, who loved him, the objects he animates turn good.
* ''WesternAnimation/StevenUniverse'' While the Crystal Gems are all thousands of years old and have effortless usage of their powers, the titular Steven is handicapped by being half human, and by being only ten years old. As such, his powers tend to work erratically. It is only when ThePowerOfLove is invoked that he can call his powers at will with certainty.
* In ''WesternAnimation/TheAmazingWorldOfGumball'', [[spoiler:Penny Fitzgerald]] turns out to be a shapeshifter whose form [[spoiler:underneath her peanut shell]] is based on her self-image. She's rather self-conscious about it, which indirectly leads to her mimicking the way people describe her (or that she thinks they're describing her).
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