After you gain Super Strength, one of the first things that happens is that you lack the dexterity and sensitivity to know when or how much of your super strength is being applied. Consequently, when trying to go about your daily grind, you accidentally break almost anything in your hands from pulling or squeezing too hard (that could include other people's hands). Jars and cups burst from the slightest squeeze, you burst through doors and windows, your shoulders chip at entrances/egresses and at worst, you cause severe damage to important facilities or even living beings. The toughest objects are brittle in your super-strong hands and you have to be extra delicate with how you hold or lift things. This is one of the most Omnipresentgags in the medium of superpowers as one of the missing Required Secondary Powers that has to be re-learned and remembered for daily functioning.
Normally, it only happens to folks who gain Super Strength, not characters born with it and who had it all their life. After all, in real life an Olympic athlete that can lift several times his own weight can also pick up a caterpillar without squishing it and it would create all sorts of Fridge Logic to see a character with long-established super strength and constantly smashing plates or bottles and not wonder how they ever managed to feed themselves without learning how to control their power.
This trope is related to Blessed with Suck but is specific to strength and to powers which resemble strength (i.e. the ability to crush objects via telekinesis). It works as a trade-off where the massive raw power that's great for a battle makes Mundane tasks hell to perform. Another variation involves Functional Magic or Psychic Powers, where a mage or telekinetic who could decimate armies with their powers have to do chores by hand, because they lack fine control. After all, when you're incinerating enemies, "Too much fire" isn't really a problem. Sometimes leads to Stronger Than They Look.
If the hero's family is unaware of his powers, undoubtedly the blame for the damage will fall on 'shoddy construction' or on another house member's bad attempts at DIY.
A frequent and more realistic variation of this is that the hero is able to control his strength, but when tempers flare or the hero is startled (or otherwise incapacitated, or perhaps inebriated) that control quickly lapses.
Compare And Call Him George, when it happens to (formerly) living things. Related to Power Incontinence. Could be called the inverse of Gentle Giant.
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A McDonald's commercial for the Disney Hercules movie had a boy ripping the door off his car with the explanation that hanging with Herc rubs off.
Anime & Manga
During her early life in a highly enhanced prosthetic body, the Major of Ghost in the Shell had some major (no pun intended) difficulties controlling the prosthetics' strength. She mentions (and it is shown in the opening credits) that she once smashed a doll by being unable to control her own limbs.
Muay Thay God of Death Apachai Hopachai in Kenichi: The Mightiest Disciple. Also a Gentle Giant on his own right, he is really kind to all living things, being even able to speak with animals. Unfortunately, due to the Training from Hell he went through during his childhood (and the fact that he was thrown in life-or-death battles even as a kid) he's incapable of sparring with Kenichi without delivering several blows that would have killed anyone less resilient. It gets to a point when Kenichi loses the memory of being hit due to a concussion.
He's actually killed Kenichi at least once. The other masters are able to revive the poor kid, and it's been mostly played for laughs.
Kenichi himself gets into this early on. One of the more humorous examples has him giving a "light" slapping to Niijima, and manages to knock him out instead. Somewhat justified, as Kenichi had been a total weakling not too long ago, so he's not at all used to having to hold back his strength.
Played more tragically during Kenichi's fight against the Tirawit Koukin trained Karate club. While they received training in attacking and were pretty good at it they received none in defending. That's why when Kenichi used his normal strength against them, one blow was enough to send them to hospital. Tirawit points out how Kenichi doesn't even realize how much stronger he is than average humans.
During the filler episodes leading up to the Cell Games in Dragon Ball Z, Goku and Gohan had this problem as Super Saiyans. Needless to say, Chi-Chi wasn't amused. The viewers were, though. This made sense, because they'd never gone through everyday, non-combat life in Super Saiyan form before.
During one of the tournaments, contestants are qualified to participate in the fight by punching a machine that registers the force delivered. Goku and his friends have to concentrate really hard to hit the machine without breaking it. Vegeta doesn't hold back.
Though considering they also had to make sure to hit the machine hard enough to qualify, this is more justified.
Before that, when Goku wants to train Gohan in preparation for the Androids, while Goku attempts to calm his wife Chi-Chi down he pats her on the back, causing her to fly through a wall and a tree. It worked.
An earlier filler example happens when Goku recovers from his heart illness, and he and Chi-Chi do the "happily toss into the air" bit when they reunite. Goku, momentarily(?) forgetting his own strength, accidentally tosses Chi-Chi too far (as in, too high to see). She didn't really seem to mind, probably since it reaffirms his aforementioned recovery.
His youngest son, Goten, unknowingly achieves Super Saiyan for the first time while training with Chi-Chi. He promptly kicks her, assuming she'll still be faster than him and dodge. She's not, and flies about twenty feet into a tree. She's perfectly fine, and not the slightest bit angry, just upset that her youngest son is already an alien killing machine.
Even Chi-Chi herself gets in on the action. In an early episode, while waiting longer than usual for Goku to return home (he may have been dead at the time), she decides to wash the dishes. About every other dish gets squeezed so hard it cracks, then dropped into a convenient garbage bin.
For all his embarrassing defeats in Z, Yamcha's still strong enough to wreck an ordinary weight machine with one tug.
The very first time this trope was in effect was during the preliminary matches of the 21st tournament. Goku playfully tapped his opponent (a big, muscular man) in the back of his leg, causing the man to fall out of the ring in pain. Goku quickly told Krillin to be careful from then on. It had been a while since Goku and Krillin had fought somebody who didn't have super-strength on par with their own, after all.
Being a combat Cyborg blessed with Super Strength, Subaru mentions her fear of performing this trope during a flashback. Also illustrated in the Magical G Irl Lyrical Nanoha Strikersmanga during a wall-climbing exercise, when a Teana that just met her asked her to put a little more strength in boosting her up, causing the now terrified girl to achieve her dream of taking to the skies a lot earlier than she expected.
Since she received her powers by fusing with a Great Big Book of Everything containing the strongest spells in the multiverse, Hayate literally cannot use low-power magic. As a result, the TSAB normally treat her similarly to a tactical nuke, only calling her in to cast a single spell in certain situations (and after evacuation orders have been given). Which is odd, given that Rein Eins' usage of spells like Bloody Dagger show that Hayate should, at least in theory, be able to fight at the anti-personnel level.
In a sound stage of A's, after Shamal forgot to heat up the water for bathing Vita asks Signum use her magic. She answers that she lacks finesse for smaller tasks.
A physical strength example occurs in Vivid, when Miura Rinaldi, one of Zafira's students in martial arts, accidentally breaks the wookden pole she uses for training soon after it was fixed.
In the Anime/Manga series Get Backers, one of the repeating causes of the main characters' crushing debt is the fact that Ban can't seem to control his strength when he is in a bad mood. As a result, he and Ginji frequently find themselves having to pay for damages to the Honky Tonk as a result of Ban breaking everything from coffee-cups to plates, tables, bars, doors, windows, and even walls.
Ryoga from Ranma ½. Whenever his emotions get too much, or his mind wanders, everything he touches tends to crumble around him. Combine this with the fact he gained the ability to shatter inanimate matter with a finger jab early in the series, and you've got a man who has as much trouble not destroying Tokyo as he does navigating it.
There is also a storyline in which Akane gains Super Strength due to accidentally eating food called Super Soba, and briefly falls into this trope. She first discovers her newfound strength when she casually sets her bowl down, and promptly smashes the table and the floor below the table. She would also regularly pat other characters (usually Ranma) with what was supposed to be a light touch on the head or shoulder, and instead sent them flying.
During a mid-manga story, Ranma is weakened by a vengeful Happousai. The cure involves a painful-looking moxibustion technique applied on his back — out of reflex, he tries to swat Cologne off his back, only to find himself smashing a solid concrete roller (the kind used to flatten sports fields) purely by accident.
It's played up more in the manga version, but Shampoo often destroys things around her, tearing through walls rather than going for the door or shattering doors when she does use them. It's debatable whether she counts for this, though, as it's just as likely that she just likes to show off that she's a Cute Bruiser. Though when given a hypnotic suggestion to "go home peacefully" she still smashes through a wall as she leaves.
While Gaou in Eyeshield 21knows how strong he is, he doesn't understand the very idea of "holding back", and is thus completely unable to do so in any situation. The same can be said for Husky Russkie Rodchenko. Kurita, on the other hand, is too strong and too friendly for his own good, meaning big, painful hugs all around.
Shin also does this from time to time, usually with electronic devices.
Roy: Without my vision I can't limit the blast properly!
Hawkeye: Don't limit it at all!
Major Armstrong is feared because of this. He hugs others and causes minor-tosevere injury while doing so. When seeing Edward injured and in the hospital, he was so emotional that he hugged him to the point Edward needed a full body cast.
Durarara!!'s Shizuo Heiwajima is prone to this, especiallywhen angry. At one point the Yakuza even deduce Shizuo's recent presence in an apartment complex simply by the state of the stairway's guardrails — which is not very difficult, as Shizuo managed to utterly destroy them on his way out.
In Super Robot Wars Original Generation: The Inspector, Lamia listens to a rather heartwarming speech from Kai to Ryusei and Bullet about trying to get the captured Arado to make a Heel-Face Turn of his own will. As the speech finishes, Excellen cheerfully points out to Lamia that she's accidentally twisted the handles of the exercise machine she had been using into a pretzel.
In Tiger & Bunny, it's implied that Kotetsu had this problem back when was a child ("I'm not supposed to touch anyone when I'm like this. I'll hurt people."), which was why he was ashamed of his NEXT abilities up until he encountered Mr. Legend.
Sakura Haruno in Naruto. While training with Tsunade during the time skip of the original series, Sakura acquires the same herculean strength that she has. But of course, whenever Naruto does anything Sakura thinks is stupid, she gets the urge to pound the tar out of him and sends him flying with just one punch.
Played for Laughs in one meme When Naruto gains Biju Mode, he accidentally hit one of the Bijudama into one of the Alliance formations, indirectly wiping it out because he couldn't control his strength.
The Rogue Titan in Attack on Titan tends to hit so hard that it wrecks its own body along with whatever it's hitting. Fortunately, it's Healing Factor helps to make up for that.
The comics version of Superman is the primary aversion of this, where his strength is almost always played as a positive and the negatives are rarely highlighted.
One story from the '90s saw Supe's strength start increasing exponentially. This trope definitely came into play then.
Some versions of Krypto the Super Dog apply this trope. Being just a dog, he really doesn't know his own strength.
Many, many times in various Superman comics would other people gain Superman's strength. This trope almost always applies.
An excellent 1960s issue of Superboy dealt with a villain tricking young Supes into thinking he had accidentally killed Lana Lang with a careless display of strength. Grief-stricken, Superboy turns himself in to the police and sits brooding in a jail cell, giving the villain and his mooks a free window of opportunity to commit crimes unopposed. Naturally, it's all a ruse, and Lana turns out to have been merely kidnapped and is totally unharmed.
In Infinite Crisis, a character named Superboy Prime (he's from the real world) attacks the DCU's Superboy, beating him badly whilst causing a huge amount of damage to the town of Smallville, until a (fairly large) group(s) of other heroes arrive as back-up. When a heroine named Pantha calls him a 'stupid kid', he retaliates by proclaiming that he isn't stupid, seemingly with the intention to merely smack her across the face...... He ends up taking her head off and killing her, visibly shocked when he notices the blood on his hand.
In Superman Annual #8, Pounder, one of a far-future League of Supermen in who have each been genetically engineered to have one of Superman's powers, has support staff who have to do everything for him, because it's not safe for him to touch things. (The whole League is Blessed with Suck, in fact.)
In Superman: Secret Origin, a teenage Clark Kent, who's powers were just beginning to emerge, really had no idea how strong he was. It caused problems when he tried to play football with his friends and accidentally broke Pete Ross's arm.
On the other hand, Supergirl does this in on occasion, for example in one of Redan's Batman and Superman comic strips. Then again, she was still learning to control her powers.
One of the explicit differences between Superman and Supergirl is that Superman has mental blocks he imposed on himself so there's an upper limit to how much power he'll use, while Supergirl has no such blocks, allowing her to at times be stronger than her cousin.
Stronger, not better. When they fought, Superman easily defeated and immobilized her (and actually threatened he could do it any time he wanted to if need be). Supergirl has been using her power for one year or two. Superman has been fighting people more powerful than he allowed himself to be since he was twenty.
According to the novelisation of the Death and Life of Superman, Superman becomes aware of these blocks and bypasses them as anything less than 100% of his strength won't be enough to take down Doomsday. He starts unleashing the kind of punches that he would never use against a different opponent.
Also lampshaded in the original comic from time to time. One story involved the Parasite draining Superman's ability to self-limit his powers. Superman wrongly concluded that his powers were growing beyond his ability to control them. He correspondingly took steps to weaken himself, which is exactly what the Parasite wanted.
In the 1970 story "Supergirl's Lost Uniform", Supergirl while in her Linda Danvers identity lifted what she thought was a fake 500-lb weight and twirled it like a baton. The fake was the one next to it. Oops.
Jack in the comic book Next Men cannot control his super-strength and has to be guided places so he does not break objects by accidentally brushing up against them.
In X-Men, when Colossus is stuck in transformed form he gets angsty about people seeing him as a monster. He then proceeds to try and call his team from a phonebooth but since he is frustrated, trying to dial the number causes his fingers to punch right through the phone.
This is somewhat justified, as he is also both much larger and much stronger than before his injury, and had been spending all of his time up to this point at Moira MacTaggart's infirmary. The caption also says he trashed the phone because he was still not used to his greater strength, not frustration. The cause for his greater size and strength was also implied to be Magneto's attempt to 'heal' him magnetically.
Done tragically in The DCUElseworld story "Created Equal". The second issue of the two-parter starts In Medias Res just as a five-year old Alex Kent has accidentally killed his mother, Lois, by hugging her.
In Nextwave, the narration mentions that the Captain once knocked a man's lungs out of his chest by patting him on the back... but in his defense, he was drunk.
The titular character in Concrete is very much Blessed with Suck in this regard, being a half-ton stone man who doesn't dare try to hold anything breakable.
The titular character in Monica's Gang suffers because of this. Since she's only 6, it leads to really funny situations (although not as much funny for her parents, that have to pay for the broken stuff, or for Jimmy Five and Smudgy, that have to feel in their skins what her inhuman strength causes. Of course, all in the Amusing Injuries territory, since it's for kids.
In a Wolverine series, there is a grown-up mutant with super strength but the intelligence of an infant. A horse tries to kick him and he punches it, then he gets upset because he can't put the horse's head back on.
The JSA recently introduced Citizen Steel, who literally doesn't know his own strength — the accident that gave him his powers also deadened his sense of touch, meaning he can't feel how much force he's exerting. He walks around in a costume he was cast into so that he can control it.
Obelix from Astérix does seem to know his strength... he is just apparently unaware that not everyone possesses that strength, hence his failure to understand the difference between "knock the door" and "smash the door" and why no one around him is able to carry tiny menhirs.
In the last issue of the Marvel MAX Barracuda miniseries, Barracuda pats the young hemophiliac he had been charged with turning into a cold blooded killer on the back... killing him. To be fair, Barracuda is a fucking beast of a man, but that's... dag, son.
In 52, being a god-empowered superbeing stopped being fun for Osiris after he killed his sister Isis' attacker, the Persuader, by flying into him too hard.
A lot of humour stemmed from the use of this trope in the 1970s comic strip Wee Ben Nevis which featured in The Beano. This trope is also frequently used in The Dandy's most famous strip Desperate Dan.
The titular character from Irredeemable also fits this trope. Basically a Superman expy, in one scene where he visits one of the many sets of foster parents he had as a child, we see him feeding their severely disabled (adult) biological son. Turns out he was there the day that Jr. came home from the hospital with Mum...he just wanted to give his new baby brother a hug...
present all over in Savage Dragon: Smasher taking the head of her husband with a single punch, Dragon killing Solar Man when the latter lost his powers in midfight, both resulting in messy Your Head Asplode moments. Those are just two of many examples.
She-Hulk, who provides the page image, is usually not an example. However there's a recent(ish) storyline where she works out like crazy to beat a much stronger opponent (she intelligently uses a quirk of her physiology which increases greatly, in her Hulk form, the effects of workout in her "normal" form). This increases her strength to the point that she breaks nearly everything she touches, until she gets a Power Limiter suit.
One Lucky Luke story had a pathetically wimpy guy (he has to carry lead weights so the wind doesn't blow him away) turn into a musclebound human nearly overnight with Luke's help. However, he has difficulty adapting, and crushes glasses he's trying to pick up and rips the saloon's doors off.
Becomes a source of angst for The New 52 version of Superboy when he realizes that he can't be around ordinary people without killing them.
Carly and Sam from iFight Crime With Victorious, particularly Sam. When Sam first receives her power, unknowingly, she tosses a soda can at Freddie that knocks him off his feet. Carly, more level-minded, runs into this problem less often, but using it is still a very volatile process.
Because of the nature of his training he knows martial arts but he doesn't remember any experience with them, including the specific effects of his attacks on opponents. After the fight on chapter 12, Iyouji was surprised when he had to ask how bad were the injuries he made on the Mooks.
In a later chapter, a Fictional Document reminded that while getting new powers were good, one should also learn to be careful with them.
And the time he petted the bunny too hard. And then did the same with Cyclops.
Paul, in spades, in With Strings Attached. Compounded by his having two levels of strength, “low” (where he can lift about 8 tons) and “high” (where he can lift at least 90 tons). After practicing day and night (literally) for several weeks he can act relatively normal at “low” strength (though he still breaks things if he doesn't take care); however, at “high” strength, which he tries not to use unless practicing, he can just barely function in the real world. He is continually conscious of his strength, so that in proximity to other people, he hardly moves, and he never makes sudden gestures.
Comes up frequently in Buffy the Vampire Slayer fanfics, particularly those depicting newly-activated Slayers. This is usually how they prove to others that something weird has happened to them.
Kallen Kozuki in Justice Society of Japan, to the point that even reaching for a glass of milk without breaking it becomes difficult.
In Justice League of Equestria, Rainbow Dash first learns of her newly acquired super strength when she kicks a tree and makes it explode into splinters.
Films — Animation
The Incredibles. Mr. Incredible got very stressed out the day he was fired and broke a number of things. He dented a doorknob, shattered the car's window, and cut straight through the plate and part of the table when cutting his son's steak. He's usually in control though, capable of doing little fiddly things with his hands even as he holds up something gigantic.
Lest we forget, he also threw his boss through seven walls. However, he arguably did that on purpose in a fit of rage, seeing as how he grabbed him by the neck to do it.
In Monsters vs. Aliens, Ginormica initially has this problem after discovering she has super strength (more than her massive form should have, at any rate). She ends up nearly crushing Derek in her excitement to see him again. Other than that, though, she manages to keep a handle on it.
This is a recurring problem for the titular protagonist of Wreck-It Ralph. He has a tendency of breaking things even when he doesn't intend to, going so far as to accidentally wreck up the Nicelanders' apartment complex during their game's anniversary party and kill Fix-It Felix Jr (it was okay though, he respawned).
Films — Live Action
Jason Voorhees has this happen to him in Friday the 13th Part VI: Jason Lives, when he throws Bert into a tree and, much to his surprise, tears his victim's arm off in the process.
Sky High has the Commander keep a couple of those mobile landlines in a drawer in case he breaks one on a rant.
Also, once Will gets his super strength, he accidentally rips his front door off its hinges by opening it.
Played with in Up, Up, and Away. The protagonist is born into a family of superheroes, but was born without a power. In order to convince his family that he's not a loser, he rigs certain things to fall apart as he uses them, such as taking the screws off the door hinges to make it appear he ripped it off. Played straight with a Noodle Incident for his father, who apparently did quite some damage to his house's foundation.
Interestingly, this convinces everyone but his grandfather, who saw right through the ruse.
One more word: Hancock. Though in his case, it's more a case of him simply not bothering to check his superstrength.
In the Fantastic Four movie, The Thing is prone to doing this with drinkwear, though it could also be related to reduced sensation with his new skin making it hard to tell how much he's squeezing.
His jaw muscles also increased in strength with the rest of him, as he's seen accidentally biting through the tines of a fork.
Also, few chairs support his weight any more, but he doesn't always remember this.
The Autobots of the Transformers movie basically destroy Sam's backyard, though that's mostly due to scale issues.
The problem isn't so much scale (since Autobots vary quite a lot in size the larger ones do have to deal with the problem in their own environments) as not being used to environments filled with small, relatively fragile things, having just recently arrived on Earth. They were pretty good about not damaging animal life forms, at least.
In Superman Returns, Clark accidentally breaks the glass in the picture frame he's holding when Jimmy surprises him with the information that "Lois is a mommy".
In Kamen Rider The First, Hongo Takeshi runs afoul of this trope in a non-comedic manner, trying to save a little girl from being hit by a truck. He scoops her up a little too forcefully, and while he does save her life, she has to be hospitalized anyway due to the pressure he put on her body.
At the end of Young Frankenstein, the Monster accidentally rips off Inspector Kemp's wooden arm while shaking hands. Understandable, as the brain hasn't been attached to that body for very long..
In the background material for The One, Yulaw was first revealed as an interdimensional offender by a fellow agent who long suspected him. He did it by asking him to carry a case upstairs and then revealing that the case was, in fact, loaded with extremely heavy weights and cannot be lifted by a normal person. Yulaw picked up the case and carried it with ease, likely thinking it was full of books. When the agent (a multiple black belt) confronted him, he ended up getting thrown down the stairs and paralyzed from the waist down. Also happens in the film with Gabe Law, who is starting to discover his newfound strength (by accidentally breaking a rifle in half).
Moonraker. Jaws tries to pull the ripcord on his parachute...it comes off in his hand. Later on he's chasing Bond in a speedboat, realises he's heading for an Inevitable Waterfall and tries to jerk the steering wheel to the side; it also comes off in his hand. Being Made of Iron he survives both Oh Crap moments.
This happens a lot to Mary Beth Layton in the book Superpowers. She first discovers her super strength by breaking a door knob. And a door. And the refrigerator door handle. And a pitcher. And the phone. And the toilet, the TV remote, a broom and most of her plates and bowls. She also slips up and breaks her boyfriend's ribs during sex, and beats a man to death by accident.
Wow. You'd think she would have figured it out by the third or fourth broken object.
The trope is present in Soon I Will Be Invincible as one of many background details. Doctor Impossible breaks the handle of a toilet, the cyborg Fatale's weight makes hardwood floors creak and cracks tiles, and she can't use normal furniture.
Carrie: Believe it or not, the titular character didn't initially intend to kill anybody, but when she accidentally did, she snapped and decided everyone deserved the same fate.
Perhaps the Trope Maker is the protagonist from Philip Wylie's Gladiator, the character credited with inspiring the Superman mythos. His superpower is basically superstrength, and it does him no good at all in this world. He accidentally kills a man playing football, gets fired from a manual labour job because he's making everyone else look bad, gets fired from a bank job because he saves someone from suffocating in the vault, and they want to know how he opened it... The entire novel is about what, realistically, it would be like to live with superstrength. A very modern look at a superhero before there were superheroes.
Used in Richard Scarry's books. Hilda, an anthropomorphic hippo child, accidentally rips a door off its hinges when she is told to open the door so the students can go out to play. Later, when the door is fixed, she rips out the door along with part of the wall when she attempts the same thing.
Lampshaded when she states, "Oh dear, I'm as strong as ten average little girls." Which causes one to wonder, how strong are the girls in this universe?
Perhaps Hilda doesn't really know how strong an average little girl is?
In Twilight, Edward mentions something to this effect...
Edward: You have no idea how delicate you are. I could reach out, meaning to touch your face, and crush your skull by mistake.
Bella gets this in the fourth book because brand new vampires are so damn strong. She hugs Edward and actually hurts him, something nearly impossible to do to Twilight vampires. Emmett, widely regarded as by far the strongest Cullen, is completely overpowered in the weeks immediately after Bella's transformation.
In What Fire Cannot Burn by John Ridley, Mutants with Super Strength do their best to avert this, but they must concentrate to avoid applying a little too much force. "Your sweaty nightmare — 'Hey, do you want to hold the baby?'"
The Six Million Dollar Man: Steve Austin accidentally broke a man's wrist in the original book. Ironically, it was right after that man figured out that Austin's bionic hand had developed a feedback that would allow him to judge how much pressure he was exerting — once he got used to it.
That's hardly the worst thing he (unintentionally) does. He also breaks Curly's wife's neck, leading to his Mercy Kill at the hands of George and one hell of a Downer Ending.
Curley picks a fight with Lennie; it doesn't end well for Curley. Lennie's scared to fight back, but once he does, all Lennie needs to do to stop Curley is squeeze his hand so hard that Lennie breaks his bones.
Derek Souza in Darkest Powers is a werewolf with an incredible protective streak over the people he cares about, which leads him to do such things as throwing another boy into a wall and breaking his back, nearly tossing Chloe across a room while merely trying to keep her from stomping off, and breaking Liam's neck, killing him - and all of this completely by accident.
Granted, nearly all of the main characters with the exception of Simon could probably fit under this trope, as their DNA has been tweaked, thus making their individual abilities much, much, much stronger than usual and leading to random outbursts of power. Most notably Chloe's accidentally raising the dead in her sleep, Derek's already mentioned feats, and Liz's telekinetic tantrum right before she is taken away and murdered because she cannot control her powers.
The magic version is used in the Tortall Universe. Most wizards can put out a candle by magic; if Numair tried it he'd just cause an explosion.
A bit of a Running Gag in the Star Trek Novel Verse whenever a character has to have a missing limb replaced with a "biosynthetic" prosthetic. One engineer manages to crush his communicator in his new hand, and remarks that at the moment he can punch a hole in a wall for a power coupling but holding an egg or shaking hands would be problematic.
The Halo novels explain that John experienced this following his augmentation surgery, leading him to wonder if the artificial gravity in the gym where he was exercising had been reduced. Shortly afterwards he was forced into a spar with several veteran soldiers and accidentally killed two as a result of this trope.
It's pretty much stated that the fight was deliberately set up to test John against four experienced ODSTs. Since then, there's been bad blood between the Helljumpers and the Spartans.
Scarlet of the The Ultra Violets, mostly thanks to her powers being superhuman dancing skills before the super-strength kicked in.
Live Action TV
Bonanza: The Season 2 episode "The Ape" used this trope as its centerpiece: a lonely, mentally challenged man named Arnie desperately seeking both love and a chance at owning his own farm causing great physical harm to people who cruelly mock him. Hoss sees potential in Arnie and tries to mentor him, but his efforts are always thwarted by Arnie's desire to marry a barmaid, Shari, who wants nothing to do with him ... and Arnie's own temper and inability to realize that, due to his tremendous strength, he can kill a man rather easily. Hoss repeatedly tries to warn Arnie that he doesn't know his own strength. Before the episode ends, Arnie indeed kills at least two people: a Ponderosa ranch hand who had mocked his slow, awkward ways; and Shari, after he attempts to gift her with an expensive strand of pearls), who slaps the necklace away and tells him he's just a big old, dumb "ape" (Arnie grabs the much smaller Shari by the neck and shake her violently, until she dies). When Hoss realizes what Arnie has done, he tries to get Arnie to understand that he killed someone (and possibly a second person, too) and that he has to go to jail. Arnie then knocks down Hoss and tries to flee. When a sheriff's posse surrounds Arnie, he picks up a huge boulder and attempts to hurl it toward everybody, forcing them to gun him down.
This trope was formerly named "Ace Lightning Syndrome", after the titular character in the CGI-animated TV program Ace Lightning, who had quite the tendency towards smashing his human sidekicks' household appliances when he arrived in the 'real world', super strength and all (not to mention his need to absorb energy in order to survive resulted in the destruction of much electrical equipment. And apparently Mark's family's electric bill was costing them a fortune).
She accidentally smashes her alarm clock with her super strength, then sweep the pieces into a drawer of likewise broken alarm clocks.
In "The Initiative" she accidentally tears the handle off a yogurt machine in the college cafeteria and makes a mess.
There are several occasions when Buffy hugs someone too hard and has to be told to let go. When she glomps the surgeon who tells her Joyce's operation was a success, his ribs creak ominously and he shouts in pain.
During the season one episode "Witch", she accidentally throws one of her classmates across the gym during cheerleading practice.
In "A New Man", Giles awakens one morning as a large and powerful demon after being cursed. He walks through his home and accidentally tears the banister off of his stairs, smashes a phone when he tries to call for help, rips through his favorite shirt, and breaks the front door off its hinges. The irony of course is that Giles is normally a mild-mannered British librarian.
Played with on Charmed when a spell cast on their police buddy gave him Superman-like strength and invulnerability. Has him accidentally ripping the door off a police cruiser, but only mildly bruising the suspect.
Eun Bi, an ex-high school delinquent, from Flower Boy Ramyun Shop says this after playfully hitting Ba Wool around the back of the head and he comments that it really hurts.
Happens to Gilligan on Gilligan's Island in the episode where the castaways ate radioactive vegetables. Gilligan ate a lot of spinach, giving him super strength.
An episode of Hercules: The Legendary Journeys takes place in modern times and involves the creators of the show going on a retreat in order to improve the show. The star Kevin Sorbo also comes along, except that he's really Hercules (yes, a Greek demigod pretending to be an actor playing a Greek demigod). During a dinner outside, he gets over-excited and slams the long dinner table, breaking it in half. The host blames the rotten wood and laughs it off. Of course, it's revealed at the end of the episode that the host is, in fact, Ares in disguise.
In UPN super-spy show Jake20, the main character mostly dodged this because his powers were mostly by activation; nevertheless, there was at least one occasion where his little brother pissed him off, resulting in him accidentally breaking off the handle to his car door. He also put a ton of holes in the walls of his apartment trying to gently tap in nails.
Early on, Kintaros from Kamen Rider Den-O suffered from this, or at least K-Ryotaro/K-Masaru(first possessee), breaking everything from park benches to lamp posts.
In Lois and Clark, after being exposed to red kryptonite, Clark's powers get boosted beyond his control. His strength gets boosted to the point that when he hugs Lois, it gives her bruises on her arms, turns their place into a mess after he sneezes and accidentally breaks a chair from getting up too quickly.
Surprisingly, doesn't happen much in the episode where Clark gets Laser-Guided Amnesia and forgets who (and what) he is. His dad has to hit him with a baseball bat (the only time when a father saying "It'll hurt me more than you" while hitting his son is true) to prove it.
The Price Is Right: On numerous occasions during the Bob Barker era, overly excited contestants who were Samoans would pick up Barker, bearhug him, and otherwise get very affectionate with him, causing him brief physical discomfort. Often, but not always, these instances occurred after the contestant won a pricing game. A running joke was that, every time a Samoan contestant appeared on the show, Barker would claim that a past Samoan contestant injured him (before playfully admonishing the new contestant to keep her distance). This gag was downplayed and eventually forgotten upon Drew Carey's appointment as host, and never came into play with either Dennis James or Tom Kennedy.
In Smallville, in Blank Clark has his memories removed, resulting in him ripping the door to his home from its hinges as he literally doesn't know his own strength.
Chloe once winced when he grabbed her shoulders with unnecessary force.
In Persona, when Chloe admits she couldn't help with what he is doing, Clark grabbed her arm forcibly, only to let her go quickly. It tipped her off that he is actually Bizarro.
In Warrior, a newly empowered superhero accidentally crushes Chloe's hand.
This happens in an episode of Stargate SG-1. Jack, Sam, and Daniel are all equipped with an alien wristband that enhances the wearer's speed and strength, if only for a limited amount of time. In the episode, Jack crushes a grip-meter and accidentally takes a chunk out of General Hammond's wall just by lazily kicking it. He also knocks Sylar off a balcony while trying to high-five him. In this case, said alien tech grants super strength and poor judgement. Sylar was a genuine accident. The other two times were demonstrations of his strength, just poorly thought out.
They also got into a bar fight, earning themselves a rebuke from General Hammond. After all, with their strength and speed, they could have easily killed those guys (especially since Jack is a Colonel Badass).
In Star Trek: Deep Space Nine Worf (yes, that Worf) relates a story of when he was 13, playing soccer and accidentally headbutting a player on the opposing team. Since Klingons are much stronger than humans and have ridged foreheads, the other kid's neck was snapped and died of his injuries shortly after.
Notably averted with Data of Star Trek: The Next Generation, as he has super strength, but refrains from using it most of the time. The one time he uses it unchecked, his friends realize he's Not Himself. He's actually having his brain messed with by Evil Twin Lore.
In one episode, a Klingon captain confronts Data concerning his renowned strength and wants to test his own strength against him. It was one of the few times when Data was in complete control and you could see how much he outclassed any humanoid. It was hilarious!
In another episode, the holodeck malfunctioned replacing characters in a Wild West simulation with recreations of Data, with his approximate physical abilities as well. Some of the characters were weaselly cowards and were otherwise unaware of their enhanced strength, but others were the Big Bad of the story and also unaware of their strength.
Don't forget the last Data who was a female saloon owner who throws herself into Worf's arms after he defeated the evil gunmen. Although that was something else entirely.
In the Star Trek: The Original Series episode "Amok Time", we get a look at how strong Vulcans really are when Spock loses control and manages to completely destroy his computer terminal. Other times when Spock loses control he becomes really scary because of it.
In Greek Mythology, Herakles/Hercules got very annoyed with his music teacher, Linus, for telling him he was playing music wrong. So Heracles slugged Linus with his lyre, or with a stool... and killed him. Oops. The first evidence of thist story is in vase-paintings of the 5th century BC, making this one Older Than Feudalism.
In another version, Linus slugged Hercules first. When Hercules was on trial, he was acquitted on the grounds that "everybody has a right to return a slug".
Many of his enemies would use Mind Control to make him angry enough to smash his wife/kids/best friends/cities and then feel so guilty about it he'd go on a near-suicidal adventure in order to atone for it.
What mind control? Most of the legends have Herc really being like that.
Depends on the myth. Some versions often had Hera induce these wraths.
Ilia Muromets, one of Russian legendary heroes, was super-strong, and sometimes hurt people by things like hugging. It didn't help that he just didn't bother to get up until age 32, so he hadn't practiced social interaction much.
Another hero, Svyatogor, was literally so strong the earth refused to hold him and was thus confined to a mountain range which was somewhat less finicky.
Some variations of the Muromets story have him receive super strength, and immediately having half of it drained away so that he won't end up like Svyatogor.
Vasiliy Buslaev, a hero of the Novgorod epic cycle, is a young ne'er-do-well who doesn't realize his insane strength. This leads to people's arms and legs being casually ripped off.
In the Finnish epic The Kalevala, this trope is Kullervo's shtick. For every task he is given to do, he always does it "according to his strength," not according to what the task requires, so he ruins whatever he attempts. Tell him to fell trees, and he magics the whole forest into wasteland where nothing grows. Tell him to build a fence, and he builds a sky-high and airtight one. Later his father takes him fishing but he completely wastes the boat rowing and kills every fish in the lake trying to set the nets.
Played for laughs in The Muppet Show episode starring Christopher Reeves (way before his accident). The guest star is explaining to Miss Piggy that he wasn't at all chosen for the role of Superman on account of his strength... while accidentally tearing apart a cupboard door. Miss Piggy's reaction: "Yeah, right..."
Joshua Oliphant in Revolting People, who tears the house to bits by accident, and wrestles bears to death while trying to make friends with them. Played for Laughs, obviously.
In The Dresden Files RPG, near the write-up for the Supernatural Strength power, Harry writes in the margins that it's really easy to accidentally kill someone with a simple punch at this power level.
Although ironically this is one of the games where the rules don't really back that statement up. If you take an opponent out of a conflict in the Fate system (which The Dresden Files uses), you decide — within reason — just how exactly that happens, and thus settling for a "mere" knockout blow is just about always an option unless you're dealing with a particularly bloodthirsty GM. (On the third hand, nothing whatsoever prevents a character regardless of their "technical" strength level from being created with a relevant aspect — which could even literally be "Does Not Know His/Her Own Strength", they're freeform that way — and playing the trope dead straight to earn fate points, be that in combat, outside it, or both.)
Cyberpunk 2020 has an inset in the section about Cyberware which features Ripperjack having a bad night due to his cyberware punching through cheap concrete and crushing the big pipe he tried to grab to keep from falling into a metal pretzel.
A trailer for Deus Ex: Human Revolution has Jensen accidently cracking a glass as he tries to hold it with one of his new cybernetic arms.
Flandre Scarlet of the Touhou series possesses extreme physical strength and the ability to destroy absolutely anything at will... except she does not know how to control this power. In fact, she was locked away in a basement for 495 years as a result of her unstable and potential destructibility. According to fandom, those she "plays with" do not last long...
It's not raw physical strength, but Nadia Grell of Star Wars: The Old Republic is the only known Force-Sensitive of her species. Unfortunately, her powers grew with no one to train her. No worries about her getting Drunk on the Dark Side (she's entirely too sweet for that), but rocks and trees do have a tendency to explode if she gets too excited.
CPU Yellow Heart and her spoiler-to-name non-HDD self in Hyperdimension Neptunia Victory, who is capable of knocking enemies over the horizon without trying. Demonstrated in one of her team-up skills where she punts an enemy at a teammate, expected them to hit it back, but puts so much force into it the enemy just cleans them up on the way through.
Guan Yinping beats down stone walls for training, and it shows, as she has a tendency to accidentally rip bricks out of masonry and nearly dislocates people's shoulders when helping them up. Her issue isn't that she doesn't know how strong her is, but rather being raised in her Badass Family means her frame of reference is slightly off.
A common flaw in Magellan Academy, since most of the students are superpowered and in training. A particularly noteworthy case would be the superstrong but not invulnerable Justine Kef, strong enough to lift massive weights but with normal human bone structure. She can break herself if she uses too much strength outside of her super suit.
In thisSluggy Freelance strip, while Aylee's getting used to being Torg's secretary, she tends to accidentally drive her fingers right through the computer keyboard.
Possibly slightly averted - The MITD DOES know it's super strong (why else think of a game "who can hit the lightest"), it just still can't control its strength...
In Tales of the Questor, this happens as an one off joke when Quentyn reunites with his friend, Kestral at her engineering school. She gives him a big hug and inadvertently hurts him because her vigorous studies having increased her strength considerably and she is not yet fully in control of it.
Spinnerette: Not as bad as most, but Heather's still getting used to her new strength, as well as having six arms, as seen when she bear hugs Sahira.
The first time Walky and Joyce have sex in It's Walky!!, they wreck most of the furniture in their hotel room. As one of the hotel employees says, "Man of steel, woman of steel, bed of Kleenex."
Equius of Homestuck would like to use bows and arrows as his Weapon of Choice, but can't actually wield them without the bow snapping like a twig when he draws it. The only safe outlet for him to let off his frustration is through beating the shit out of robots in cage matches.
He also loves drinking milk. It's too bad he can't pick up a glass of it without shattering it in his hand.
Her attempt at filling up an inflatable pool causes a blast that knocks Kinka out. Seren makes a note to not teach her CPR until she's learned to take it easy.
After Kinka explains her token attempts at Percussive Maintenance on a fan that just stopped working, Tamaryu decides to help out with a "light chop" that splits the fan in half.
Zig-Zagged with the title character from Poppy O'Possum; she's very much aware of her own strength, and treats it like no big deal (to the incredulity of those around her). However, she occasionally misjudges how much strength is needed for a given situation, such as when she opens the iron gates to Eggton when the guards refuse to let her in - resulting in one of the doors becoming unhinged and being sent flying off into the nearby countryside.
Common problem in the Whateley Universe: Phase can change her density from intangible to super-dense. When she first manifested, she smashed her bathroom, bent her tub, and then went light and couldn't stop sinking through the floor. One of the things Whateley Academy teaches is control of powers. The bricks routinely have assignments like carrying a raw egg around to learn control.
Probably a better example than Phase (who for all her worrying has remarkable fine control over her powers already) would be Compiler, a girl who used her mutant gift for nanotechnology to give herself the superhuman strength and speed her mutation itself failed to provide and that she hasn't quite learned to keep from activating purely by accident yet.
Another good example is Diz Aster, who is a Brick along the same lines as Lancer - except that her telekinetic field can't produce anything less than 7 tons of force. This also means that she can't even feel anything, since her shields extend to a few millimetres past her skin; by the time Chaka starts helping out, it's been a year since anyone's been able to touch Diz — or since she's been able to touch anyone else.
An equally good example might be Tennyo — whose powers include the ability to throw around beams of energy that flood the area around her with radiation. Since Tennyo herself is immune to the effects of her powers, she's rarely aware of what's happening until it's too late. This got Lampshaded in a chapter of The Great Shoulder Angel Conspiracy, where the instructors for Team Tactics pointed out that Tennyo can't just throw radiation-heavy energy around wildly without noticing if she wants the rescue mission to be a success... so they gave her a belt-attachable radiation detector, so that she can keep an eye on the levels she's putting out.
Alfred, the Bison construction worker from Darwin's Soldiers, possesses extreme strength. Most of the time he is in control of it but if he is angry then things tend to get destroyed. For instance, he crushed a piece of concrete that he was planning to use as an Improvised Weapon. A more extreme example was when he started pounding on Aisha's door and leaves the door looking like someone had taken a sledgehammer to it. And he accidentally knocked over a vending machine while trying to free a stuck snack.
The Tick had a tendency to leave crumbling footprints embedded in the roofs of buildings whenever he went Roof Hopping.
The live-action series has a gag where Arthur shakes hands with the Champion, and Arthur clutches his hand in pain, then the Tick shakes hands with the Champion and the Champion recoils in pain.
The Tick has done the door thing, too. And generally causes massive amounts of collateral damage. It isn't that he is unused to his strength so much as that he's clumsy, insane and not very bright.
And Nigh Invulnerable, so he doesn't necessarily notice if he bangs his head on a doorframe hard enough to put a hole in the wall.
Bulkhead of Transformers Animated has this problem fairly often, in no small part to being the biggest Autobot and in a world much too small for him. In an online short, he's shown causing gale-force winds to blow away a park full of people just by applauding.
In Transformers Prime, Bulkhead says that the Autobots know both when to use force and how much to use... and breaks some of Ratchet's equipment by way of demonstration. "Hey, I NEEDED that!" Unlike Animated Bulkhead, this version isn't clumsy but it's implied that he still heavily restrains himself because even among Cybertronians he is an abnormally big and powerful bot. Part of his relationship with Miko is her encouraging him to unleash his strength when necessary.
The Justice League episode "Just a Dream" referenced this trope. When Dr. Destiny traps Superman in his worst nightmare, said nightmare involves Superman losing control of his strength and accidentally crushing Jimmy Olsen to death when he tries to hug him.
Of course, Superman's "World of Cardboard" Speech in the grand finale mentions that he's constantly holding himself back, for fear of hurting those around him.
Kim Possible had a few of these moments when she briefly ended up with the Super Strength of Hego, a Superman Expy. For most of those moments, though, she hadn't yet realized what had happened, making it a literal case of not knowing her own strength.
Teen Titans's Starfire is an alien from a planet where everybody has superstrength, resulting, when she comes to Earth, in a world-of-cardboard effect as Superman described it (not the trope). Particularly unfortunate as she fond of hugging her friends.
In Ben 10, Ben has a rarely-unlocked form called Way Big. He's a nod to the heroes of the Ultra Series and is cosmically-powered, so his strength is not simply what his size implies if you ignore the Square/Cube Law. The race's native environment is inside cosmic storms and they really aren't born to live in a world with anyone or anything that's breakable. A great deal of real estate can be obliterated with little effort if Ben doesn't keep himself in check, as witnessed once in a story taking place in the future: A villain made the grave error of hurting Ben's son. When Ben flattened him with one punch, a decent chunk of the city got flattened as well.
Bullwinkle invokes the line on himself in a bumper of his show after pulling a wild animal out of his hat instead of his intended rabbit.
The Powerpuff Girls Movie shows that the girls knew their own strength...they just didn't know how to apply it properly until—after exiling themselves on an asteroid—they sensed the Professor was in danger.
Really Really Big Man, the resident superhero of Rocko's Modern Life, suffers from this problem, especially in his day job as a mild-mannered (female) reporter, as he cheerfully walks into the office, ripping off doors and smashing holes in the floorboards with each step. Even as his heroic self, he seems somewhat unaware of just how potentially destructive he can be, as those lovable little Poots find out to their cost...
Ed Eddn Eddy has several characters such as Ed, Sarah and Rolf showing feats of superstrength, and sometimes (mostly Ed) causing collateral damage because of it. In "Eds-aggerate", Rolf even hangs a lampshade when he pulls some of the kids out of a pipe, they get sent flying and land on a wheelbarrow full of dirt, catapulting the contents right onto himself.
Rolf: Rolf is too strong for his own good.
There's a nervous system disorder that prevents people from telling quite how much pressure they're applying to something — though unless they're ridiculously strong, it's rarely ever a problem.
Or unless they're handling something light and delicate, like paper or a neurosurgical operation.
Inverted (cruelly) with with leprosy. Its' not that they injure others, but that they injure themselves since they lack the sense of touch. Couple that with high rate of infects leads to gangrene and disfigurement. Thankful there is a cure with a specific antibodic regiment.
Though nowhere near as extreme in fiction, can happen with some people devoid of any nervous disorders. Common with young men who are just realizing that they've suddenly gained a bunch of muscle mass.
And athletes. It's not uncommon for water polo players to under-estimate their strength and over-estimate the other player's strength, and dunk someone/give them a nosebleed/really hurt someone without realizing it.
Basketball player Charles Barkley once hugged a teammate into the emergency room. WHOOPS!
Even non-athletes can hug hard enough to seriously restrict breathing, especially if two people hug someone at the same time.
Beyonslay may fit this trope. Look at what she did to Rice Rocket!
People who hit their growth period before their peers can exhibit this.
Sometimes it sticks, particularly for those who end up very large. It can be hard to estimate just how much damage you can do when you don't work out but are still 6+ feet.
Scientists are currently working on robots that are made of soft materials, because hard ones are not equipped to handle delicate objects. Really hoping it wasn't some kind of medical/child device that led them to this conclusion.
Don't worry, it was eggs.
Sadly, lots of small children learn this the hard way with their first pet, especially if they mistakenly try to ride a dog or a cat like a horse, which can cause serious back injuries to the pet.
Individuals with frequent seizures can be abnormally strong, which is why you either get a half dozen people to help sedate one who is out of control or you have one try to gentle calm them down.
This is not so much "abnormally strong" as that they don't have the natural limiters on using their strength and are instead flailing about uncontrollably. A normal person knows not to hit something that won't move, like a wall, with their full strength. A person having a seizure doesn't have that option.
In athletics in general someone may see their physical strength improve with regards to one specific area (like weight training) only to not realize how it translates into another sport. Thus you start playing basketball and suddenly shoot the ball over the backboard. Or a friend starts to playfully wrestle with you and you lift them off the ground.