->''"The krogan evolved in a hostile and vicious environment. Until the invention of gunpowder weapons, 'eaten by predators' was still the number one cause of krogan fatalities. Afterwards, it was 'death by gunshot'".''
-->-- '''[[EncyclopediaExposita Codex:Krogan]]''', ''Franchise/MassEffect''

If your means are limited, you have to show resourcefulness. This is especially true if the environment one works and lives within is unforgiving and dangerous. Simply surviving in places like a WretchedHive or DeathWorld can make people stronger and tougher, and those who live in such places can be expected to be more than a match for those who don't have to spend every day simply fighting to stay alive. If the world is dangerous enough and generations of people have survived in such a place, natural selection ensures that the toughest and most resourceful will live through, and over time those who live in this environment will change to adapt.

This trope deals with people, whether individuals, societies, or entire species, that are meaner, tougher, stronger, and/or smarter than others because their home is the kind of place that breeds out those not fit to survive. Often the [[ProudWarriorRaceGuy proud warrior race/species]] come from such an environment. Applied to humanity it might imply that HumansAreWarriors. Anyone who survives to old age in such an environment is most likely a BadassGrandpa or OldMaster. When this is created ''artificially'' it is TheSpartanWay. Expect EveryoneIsArmed to be a result -- [[RuleOfCautiousEditingJudgment or occasionally the CAUSE]] -- of this trope.

!!People Who Have To Be Sharp:

* BarbarianTribe
* DisasterScavengers
* FatherNeptune
* GangBangers
* HeroicSpirit
* HumansAreWarriors
* IntrepidMerchant
* MotherRussiaMakesYouStrong
* OldSoldier
* ProudWarriorRace
* SpaceCossacks
* YoungConqueror

!!Reasons Why You Have To Be Sharp:

* CrapsackWorld
* {{Deathworld}}
* EarthIsABattlefield
* EverythingIsTryingToKillYou
* NotSoSafeHarbor
* OutlawTown
* RedLightDistrict
* ViceCity
* WarIsHell
* WorldOfBadass
* WretchedHive

!!Things To Do When You Are Sharp:

* BloodKnight
* DidYouJustPunchOutCthulhu
* GlorySeeker
* KnightErrant
* {{Plunder}}
* TheQuest
* TakeOverTheWorld
* TheConqueror



[[folder:Fan Fiction]]

* ''Fanfic/WeaverNine'': The Society is comprised of criminals, malcontents, misfits, mutants, refugees, and capes from third-world countries. They are constantly besieged by every other power on the planet who want to kill, enslave, brainwash, or study them. They are also considered (rightly) the most powerful villain organization on planet earth and have a fearsome reputation to match.
* In ''Fanfic/ChildOfTheStorm'', it is revealed Asgardians evolved [[PhysicalGod power]], [[LivingWeapon abilities]] and high level {{Magitek}} because it was that or be killed by everything else on the DeathWorld that is Asgard. It's a very pretty, very nice world, just infested with giant monsters.


[[folder: Film]]
* ''Film/AssassinsCreed2016'': In response to Sophie saying she wants to "cure aggression", Callum says that aggression helped keep him alive. This is not hyperbole; he was fake executed for the self-defense murder of a pimp.



* ''Franchise/{{Dune}}'':
** Everyone is scared into obedience by the Emperor's Sardaukar, recruited on a prison planet and trained into elite troops. Then they are thrown against Fremen, natives of [[DeathWorld Arrakis]] who had just enough industry to stay alive. The results are highly demoralizing. Fremen, upon being informed whom they faced, comment along the line of "ah, we wondered why these were ''challenging''..."
** A detachment of Sardukar in three troop transports was sent to attack a Fremen settlement while the warriors were away attacking somewhere else. A handful ''escaped'' in one transport (by using the attitude thrusters as weapons) with a prisoner from a defense force that consisted of "women, children, and old men". The kicker? [[spoiler: The prisoner, a small child, ''allowed herself to be captured, because she knew she would be brought before the Emperor'', which is precisely where the next phase of the war plan required her to be.]]
* ''Literature/TheReynardCycle'': A combination of brutal winters, recurrent famine, and the resultant decree that its citizens are only entitled to have ''half'' as many children as one has personally slain in combat has transformed the Calvarians into a [[ProudWarriorRaceGuy Proud Warrior Race]]. Want to be the mother to a bouncing baby boy? Better become a BloodKnight . . .
* ''Literature/TechnicHistory'': Several times noted of a culture. Not least the ones who like the Ythrian Domain(a confederation of clans of BirdPeople and human allies)survived the chaos between the fall of the Polesotechnic League and the Rise of the Terran Empire.
* Aiel in ''Literature/TheWheelOfTime'' are a desert-dwelling ProudWarriorRace known and feared everywhere for being extreme badasses: in the years prior to the start of the books, a coalition of all the western countries was needed to stop them, and actually failed (the Aiel returned to the desert only when they did what they had set out to). It is also implied that this was their destiny, and that they had been sent to live in the desert, 3000 years before, precisely so that they would become a reliable and powerful army for the Dragon Reborn when the time came.
* ''Literature/TheWarAgainstTheChtorr''. Chtorran fauna and flora is naturally more aggressive and adaptive than its human equivalent; scientists speculate that Chtorr is a DeathWorld where all life has to be either aggressive or lunch.
* In Literature/{{Discworld}}, this trope is used to justify InstantMessengerPigeon - Ankh Morpork rooftops are full of gargoyles, so the local pigeons have to be smarter than average. Though as Sam Vimes wryly notes, "there were things growing on old damp bread that were more intelligent than most pigeons."
* In the Literature/CoDominium universe the second most feared troops in the galaxy (after the {{Super Soldier}}s of Sauron) are from Frystaat. A [[HeavyWorlder high gravity]] world with intense heat, blinding sunlight, and [[DeathWorld lethal wildlife]].
* In Literature/TheSilmarillion the three tribes of the Edain which arrived in elven lands, had arrived their after spending generations ''marching through Morgoth's territory''.
* ''Literature/{{Worm}}'' is set in the city of Brockton Bay -- a city which experiences [[CrapsackWorld a number of severe incidents over a short period of time]]. Compared to the people who evacuated town and only returned after the worst of the disasters had resolved themselves, the people who stayed are a lot tougher and a lot more willing to engage in violence.
* Barrayarans in Literature/VorkosiganSaga. After being confined on a {{Deathworld}} with no access to technology and subjected to generations of eugenic infanticide and civil wars, they are invaded by the Cetagandans who were centuries ahead of them in technology. Miles is a special example of this, as everyone considers him a "mutie" even if he is a prince, and he is driven to succeed. As Barrayar is patterned after UsefulNotes/TsaristRussia it [[MotherRussiaMakesYouStrong makes sense.]]
* Subverted in Creator/HGWells' short story ''The Land Ironclads'', one side is from a rural environment and the other live in cities. The rurals think that they are going to slaughter the soft city-folk because they've been hunting for as long as they could hold a gun. But it turns out that human strength means nothing against [[TankGoodness superior firepower]].
* In ''Literature/WingsOfFire'', this is why Moon is so talented at hunting. She was alone during her childhood (except for occasional visits from her mother) and had no meat except what she could catch herself. (Dragons ''can'' eat fruit, but few ever develop a taste for it.)
* ''Literature/{{Noob}}'' mentions Olydri being much more hostile in the time of the {{Precursors}}, which motivated them to build an advanced civilization.
* ''Literature/TheWitcher'':
--> For decades they said about [[http://witcher.wikia.com/wiki/Kovir_and_Poviss Kovir]] that its only riches are sand and seawater. This joke was still remembered when Kovir de-facto monopolized the world market of glass and salt.


[[folder:Live Action TV]]

* ''Series/{{The 100}}'' has the Grounders accuse the Sky People of being soft, due to them not having the skills or the savage ruthlessness the Grounders use to survive on Earth. However, any character who's survived the first season has proven themselves capable of ''becoming'' skilled and ruthless very quickly.
* ''Series/GameOfThrones'':
** Northmen are of this opinion about their homeland. By the same token, the wildlings beyond the Wall see even the northmen as soft, pampered southerners.
*** Of particular note in the North is House Mormont of Bear Island. Bear Island is the ass end of nowhere to the Seven Kingdoms, located almost north of ''The North'' on a remote off-shore island, vulnerable to raids from both the Ironborn and the Wildlings. It's the northwestern corner of the known world, away from any sea lanes. On top of this, they lead a hardscrabble existence on their resource-poor island: it is heavily forested, largely untamed (albeit beautiful) wilderness filled with ''bears'', to the point that their main food source is from fishing instead of farming or hunting. Hence they are this trope.
** The ironborn have a cultural superiority complex based on this: "Hard places breed hard men, and hard men rule the world."


[[folder:Poems and Proverbs]]

* ''[[http://www.kipling.org.uk/poems_benefactors.htm Benefactors]]'' by Creator/RudyardKipling.
* Creator/FriedrichNietzsche said "What doesn't kill you only makes you stronger." Whether or not that's an example depends on how literally you interpret "stronger."
* Proverbs. "Necessity is the mother of invention". Or an old Russian variant, "the need will force you to eat pies" (instead of plain rye bread, that is).
* Ernest Rutherford said "We don't have the money, so we have to think." The beginnings of physics saw a lot of creativity funnelled into making tools and experimental devices in a barn -- sometimes literally. The early scientists used to improvise in experiments simply because there were ''no'' established methods in their area. Even Lord Rayleigh made his own equipment out of near-junk, despite being a lord in his land -- and many, many others. On the way they made ''a lot'' of great inventions. Robert Williams Wood was not only the PatronSaint of EducationThroughPyrotechnics but, as one of the pioneers of physical optics, made state-of-the-art spectroscopes using materials like sewer pipes or a tombstone, and cleaned one of these by shoving a ''cat'' into the pipe and closing it so that the cat had to exit from the other end. Oh, and among other things [[http://www.victorian-cinema.net/wood.htm he was a co-inventor of film animation and cartoon as we know these]] (you might call him the grandfather of MickeyMouse), color photography and ultrasonic echolocation.


[[folder:Tabletop Games]]

* Every time you see a DeathWorld in TabletopGame/DungeonsAndDragons, you can bet someone there is really tough and probably really smart.
** TabletopGame/{{Spelljammer}} got [[OurOrcsAreDifferent Scro]]. Orcs and other goblinoids in the First Unhuman War were cornered and pushed back by elves until they ended up in a barren DeathWorld. When they finally [[RoaringRampageOfRevenge emerged]]... [[TheJuggernaut uh oh]]. They see common orcs as backward louts for a reason.
** ''TabletopGame/DarkSun''. All of it. Even [[WretchedHive cities]].
** Underdark inhabitants in TabletopGame/ForgottenRealms. The world below the world is full of creatures incredibly tough just because the DeathWorld requires this... which in turn frequently contributes to the DeathWorld's nastiness. While the Drow prefer cheapskate solutions, they are still packed with magic to the eartips and are highly lethal whether they fight with blades or brains (their cities are [[DeadlyDecadentCourt about as dangerous]] as the wild caverns around). And the Swirfneblin are barely comparable with surface gnomes (except tinkers, who are [[CrazyAwesome just that crazy]]).
** Regional Feats introduced in ForgottenRealms 3 ed. reflect this. Those who live in the jungles learn to survive in the wild, people raised in TheMagocracy tend to know how to talk their way around problems and have an eye for magic stuff, and so on.
** The Drow in TabletopGame/{{Eberron}} are possibly the toughest humanoid inhabitants of the setting, since they live in the [[DeathWorld jungles of Xen'Drik]] and have to tangle with giants for resources regularly.
* This trope is the reason why, in TabletopGame/{{Warhammer 40000}}, one of the acceptable, if not expected, tariffs the Imperium of Mankind imposes on entire planetary governments is... Manpower. Living in a DeathWorld tends to create the sort of humans perfect for [[{{Mooks}} cannon fodder]] in a galaxy where there is only war.
** Fenris is an ice planet[[note]]It was originally envisioned as a planet with an elliptical orbit, that spends 365 days frozen over and 365 days more roasting hot. Most authors forget this and Flanderize the planet as all ice all the time.[[/note]] whose ecosystem seems to have been designed by a Myth/NorseMythology buff, inhabited by continually warring pseudo-Vikings. And if that weren't enough the Space Wolves only recruit young[[note]]Not that young means all that much, since "old" on Fenris means thirty[[/note]] warriors who fall in glorious battle.
** Catachan is a jungle where [[EverythingTryingToKillYou Everything Is Trying To Kill You]].
** Atilla is pretty much a planet-sized Mongol steppe, as is Chogris, the home of the White Scars.
** Cadia is a nice, earth-like planet. Oh, and it has the [[NegativeSpaceWedgie Eye of Terror]] for a neighbor just a spit away which spews out AxCrazy [[TheLegionsOfHell Chaos warriors]]. That Cadia's militarization and Imperial Guard troops are a model for planets all around the Imperium is no coincidence.
** The majority of [[RedshirtArmy Imperial Guard]] regiments actually come from [[CityPlanet Hive Worlds]], due to population density and overpopulation, since the planets typically have around the hundreds of billions of inhabitants per city. Most often [[WretchedHive underhive]] gangs are simply rounded up, given a flak jacket and lasrifle, than dropped onto the front lines with no additional combat training. In many cases, they don't need it.
** In a way, this is true of Humanity as a race. When you are constantly battling omnivorous monsters that outnumber the stars, invincible omnicidal Terminators, AxCrazy RealityWarper fungus aliens, psychopathic space elves, mind-controlling Communist Japanese aliens, and TheLegionsOfHell, all at the same time, and ''surviving'', you have to be pretty damn badass.
* ''TabletopGame/MagicTheGathering'':
** The Temur Frontier of Tarkir live in a snowy, brutal place that they had to grow tough enough or die trying. When the dragon Atarka takes over the clan, this trope is taken even further in that the only members of the former Temur left are the only ones that Atarka deemed worthy enough, or else they become her next meal.
** In the ''Shards of Alara'' block, the plane of Alara was split apart into five "Shards", sub-planes where one color of mana dominated with its two compliment colors, with the other two cut off completely. The White, Blue, and Green shards got off pretty easy, as Bant is downright Arthurian, Esper is a world of unquestionable progress, and even the untamed jungle shard of Naya is so full of life and vitality that it's practically pastoral. The Red and Black shards, however...
*** The Red shard of Jund is defined by constant predation. There is no "prey" in Jund; Even the smallest and weakest creatures are still dangerously venomous, and [[InstantAwesomeJustAddDragons dragons]] sit at the top of a food chain where every link is lethal.
*** By ''sharp'' contrast Grixis, the Black Shard, is very literally a DeathWorld; The mountains are large piles of bones, there are more undead than as not, the few communities of living people must constantly hide in fear of being killed, reanimated, and/or enslaved by demons. Necromancers, who usually make up a scant minority in other settings, are flagrant and abundant, as the ones who typically keep them in check are nowhere to be found.


[[folder:Video Games]]

* ''Franchise/MassEffect'': This is krogan evolution in a nutshell; their planet was so dangerous that for centuries, the most common cause of death was 'eaten by predators'. This explains why they have secondary and even tertiary organs, and why they are {{Explosive Breeder}}s.
* The Sishrak in the ''VideoGame/SpaceEmpires'' series are, by the standards of most of the other species, a ProudWarriorRace who have a reputation for being warmongers. Since they are known to be natives of another dimension who invaded the universe, it is speculated that in their own dimension they are at the bottom of the food chain and must constantly fight everything else in order to survive.
* This is the background of the Barbarian class in VideoGame/{{Diablo}}. Though they specifically reject technology and magic because they think it will make them weaker in the long run.
* The ''VideoGame/{{Borderlands}}'' and ''VideoGame/{{Borderlands 2}}'': Anyone who can survive on [[DeathWorld Pandora]] for any length of time without dying or going insane must be a degree of badass. Doubly so for the Vault Hunters, who instead of holing themselves up in the few livable cities, go exploring around the planet, which is chock full of vicious animals, insane bandits, and minions of the local MegaCorp. Made even clearer in ''VideoGame/TalesFromTheBorderlands'', where Rhys and Vaughn, {{Office Drone}}s from off-world, are constantly both shocked by the madness of Pandora and only barely able to survive it, in contrast to the natives.
* The ''VideoGame/{{Pokemon}}'' anime shows that [[MegaNeko Pyroar]] believe in this. "A Fiery Rite of Passage" depicts an alpha Pyroar forcibly ejecting a Litleo (the juvenile form) from the pride for the Litleo to show itself capable of living without the protection of the adults. Litleo is forced to dig deep to rise to the challenge. Pyroar isn't above giving a ''little'' bit of backup, though.
* In ''Videogame/LeagueOfLegends'', most of the Noxian champions who grew up without connections (i.e. on the streets) are this, because [[TheSocialDarwinist Noxians]] believe that the strong will pull themselves up on their own and the weak deserve to die. Darius and Talon are shining(?) examples of what surviving to adulthood in that environment does to a person.
* In ''Franchise/TheElderScrolls'', this is partly why the ProudWarriorRace [[HornyVikings Nords]] are so hardy. Skyrim is [[EverythingIsTryingToKillYou filled to the brim]] with dangerous predators such as wolves, bears, sabretooth cats, and frostbite spiders. [[OurGiantsAreBigger Giants]] wander the wilderness occasionally attacking settlements looking for goodies. [[OurWerewolvesAreDifferent Werewolves]] lurk in the night-time forests. The [[OurZombiesAreDifferent dead are restless]]. Ancient [[OurDwarvesAreDifferent Dwemer]] ruins dot the landscape, still full of their MechaMooks and {{Death Trap}}s. As if that wasn't enough already, [[GrimUpNorth the climate is freezing cold and unpredictable]], especially in the northern holds of Winterhold and The Pale. Even to ''claim'' Skyrim during the Merethic Era, the Ancient [[{{Precursors}} proto-Nords/Atmorans]] who settled there had to contend with [[OurElvesAreBetter Falmer (Snow Elves)]] and Dragons; the former native to the land and the latter who maintained their base of power and [[ReligionOfEvil cults]] there.
* ''VideoGame/StarCraft'' has the Zerg deliberately invoke this. They send hive clusters or entire broods to any DeathWorld they can find to force evolution upon their forces. Notable examples include Kaldir which is only ''slightly'' warmer than deep space, Char which is a volcanic planet whose only liquid seems to be an acid marsh, and Zerus where the lack of a HiveMind means [[EverythingTryingToKillYou everything is trying to kill everything else]].

[[folder:Visual Novels]]
* While growing up, [[VisualNovel/MyHaremHeavenIsYandereHell Yuuya]]'s only friends were {{Yandere}]s all competing for the same boy's affection ([[CreepyChild sometimes violently]]). Consequently, he learned the art of diplomacy ''very'' quickly and, by the game's beginning, can expertly defuse conflicts between just about anybody...and given that he's friends with or will become friends with most named characters, that skill turns out to be exactly what the situation calls for. [[note]]In a flashback set before Yuuya realized how volatile his social life was, he was much less tactful and cautious. This almost got his FirstLove killed.[[/note]]

[[folder:Web Animation]]
* ''WebAnimation/{{RWBY}}'': Ozpin observes that the normal process for qualifying for entrance into the prestigious [[ExtranormalInstitute Beacon Academy]] is to go through the usual combat education and examinations. Blake is one of the very few who did not qualify this way. Blake tells him how hard life is outside the [[DeathWorld protected kingdoms]]; if a person cannot fight, they will die. It's pure survival.


* ''Webcomic/GirlGenius'' Jägers. They are {{super soldier}}s who like to [[BoisterousBruiser kick ass, laugh loudly and drink]], not necessarily in this order -- no one expects a Jägerkin to notice everything and get non-obvious conclusions. But then there are those who wandered for many years on their own both in lands where the people remembers them as ex-conquerors and in wastelands where they are not nearly the toughest creatures...
--> '''[[http://www.girlgeniusonline.com/comic.php?date=20051007 Dimo]]''': Haff all dose guys vit de baron gone soft over de years -- or haff ve become... ''sharper'' because ve leave de group und haff to ''tink better''?
* ''Webcomic/StandStillStaySilent'': AfterTheEnd Norway and Finland both seem to have become this.
** Sigrun, the Norwegian member of the team whose profession is PlagueZombie hunter, considers salvaging for books in a ForbiddenZone riden with said {{Plague Zombie}}s while officially guarding scholars doing research a vacation. She also considers that Emil and Lalli are competent merely from not dying on their first mission and has acquired a hatred of backtracking due to having consistently gotten ambused while doing it.
** Lalli, one of the Finns of the crew, is known to have made one mistake prior to Chapter 8, and that mistake caused fellow soldiers from his military base to die. The argument that he's not the only person making mistakes didn't work on his older cousin, as their grandmother making a mistake that had dire consequences was the reason they moved from their old home to their military base when Lalli was only eight years old. In the present day, Lalli's mindset includes a ''very, very'' big stigma against making mistakes.


[[folder:Web Original]]
* ''Literature/{{Twig}}'': Sylvester holds to this as part of his...[[TheSocialDarwinist unusual views on humanity]], and as a source of emotional comfort. A ChildSoldier used as a HumanWeapon by a ruthless AcademyOfEvil controlled by an AlternateUniverse British Empire that manages to be ''worse'' than its historical counterpart, he finds great emotional strength when he encounters other children who have been used and abused, placed under immense stresses, and come out, if not intact, at the very least alive, and in a few cases even ''driven.''

[[folder: Real Life]]

* Eighteenth and nineteenth century regimes much preferred mercenaries from extremely nasty wilderness areas. A large part of this was based on this theory.
* Greek philosophers bragged that Greeks were this because of having to tend farms on their own. Persians were stereotyped as soft and wussy.
** Likewise, the Spartans believed they were stronger than the other Greeks because they spent their entire lives fighting. That attitude eventually led to their conquest of the other city-states, which Rome used as a pretext for conquering Greece.
* [[ProudMerchantRace Venetians and Dutchmen]] spent generations not only living ''from'' the ocean and fighting off all competitors but actually living ''on'' the ocean(by way of building "fortifications" against flooding). The result was that Venice managed to take over the Mediterranean for a time. And Dutchmen for a short time managed to TakeOverTheWorld.
* It is sometimes said that carnivores are unusually intelligent among mammals because they have to catch their food (which means coming up with a plan of attack and deploying it), and sometimes, fight over it among each other. While grass eaters just bow their head and eat.
** It's animals that have to use their brains (memory/lateral thinking/both) to get their sustenance (food/water/both), not just their senses (hunting requires sight, tracking scent).
** By the above theory, the ideal place for intellect to grow is in the middle of the food chain, where creatures both have to hunt for their food and have to avoid other predators. Add to that that these creatures are often not that much stronger than their prey (think wolf vs. wild buffalo), and so have to resort to teamwork and tactics to get their meal. [[HumansAreSpecial Now guess where early humans stood.]]
** Most top-level predators, however, still have to worry about other top-level predators and tackle dangerous prey, so this still applies. Almost all apex predators are highly intelligent.
* Mongols. Remember those guys who beat the Chinese ''and'' chased the Kumans into the Adriatic Sea? Not even distracted much by dealing the same way with several Russian princedoms, Hungary and most of Muslim Middle East alike? ''This'' mostly was converted tribal militia without benefits of any [[TheSpartanWay non-conventional training methods]]. Their success stems indeed largely from learning the lessons of the steppes: endurance of great hardship making them tough as nails and good at cooperation, nomadic life made everyone a good rider, hunting and warring in open field gave obvious incentives to develop the best long-range weapons around, territorial clashes of tribes and later a civil war gave them plenty of experience. The one major change Ghenghis Khan did introduce was a total replacement of the former social hierarchy with the united militarized Mongolian nation -- their men no longer paid much attention to clan affiliation, but only achievements and command structure. Subodai, his greatest general, an example of having been a 'commoner' who rose to the top. Between the hero cult on par with Greeks and a chance to beat traditional enemies, they tried to be great warriors pretty hard.
* Finns, living in the Arctic in some of the most beautiful and most rigorous terrain in the world. It was no accident that the Russians and Swedes preferred other people to pick on. See [[UsefulNotes/SimoHayha Simo Häyhä.]]
* The human hand. It is able to open and perform delicate and precise movements... or it can be balled up into a remarkably effective built-in blunt force weapon (commonly known as a "fist"). Chimpanzee hands cannot ball up into fists, and a tightly-balled fist surprisingly can weather forces that'd cause serious injury to it otherwise when used for blunt force.
** Taken further with Cro-Magnon and Neanderthal humans: It is postulated that our ancestral cro-magnons had more deft wrists, enabling them to throw shafted projectile weapons (IE: spears), while neanderthal hands were still only able to ball up into fists.
* [[UsefulNotes/TheGloryThatWasRome The Ancient Romans]] became a major military power due to this. In the beginning it was that they lived in the best commercial position of Latium, and had to defend themselves from neighbouring peoples trying to subdue them. When they had subdued all of their neighbours the Gauls showed up, sacked Rome and promised they would return, so Rome prepared to defeat ''them''. After repelling their successive attack and expanding even more to get the manpower to defeat them once and for all they had to deal with the Samnites, who were a major power in Italy and wanted to force Rome in their League. After breaking their power and that of the Gauls they had to deal with the Greeks (not just those in Italy but their mercenary armies from mainland Greece) who were helped by the Samnites, then with the Carthaginians (and again the [[TheDeterminator Samnites]] and the Gauls), then with the successors of UsefulNotes/AlexanderTheGreat, then with the Germans, then with ''all of Italy'' (led again by the Samnites. This was the last time, as Sulla exterminated them as a people and the survivors never found new allies), and so on. Note that the list includes only the wars where Rome actually risked to lose, ends with the Republic (the Empire would collect even more enemies), and doesn't include civil wars. In the end the Romans were that good because they needed to be, and most of their wars during the Republic were ''defensive'' in nature (Rome's concept of "defensive war" included conquering or exterminating the enemy to prevent another attack, resulting in almost accidental expansion). It has been put thus: Romans are the only people who ever conquered the world in ''self defense''.
* The Gurkhas, "Sardaukar" of the British Empire. To quote British Field Marshal William Slim: “If a man says he is not afraid to die, he is either a liar or a Gurkha.” Growing up in terrain that would give the Mongols pause is certainly good practice for some of the places they've gone to war.
* In both world wars Britain sent units from Canada and Australia to the front lines, partially because it was believed that living in frozen tundra or a desert filled with poisonous animals made them tougher, and partially because colonials were considered more expendable. The Germans [[TheDreaded learned to fear them]].
** ...[[InvokedTrope because they were rumoured to torture and kill enemy wounded and any enemies who tried to surrender]]. We don't know the extent to which these rumours had a basis in fact because reports of them doing so could have been exaggerated by the units to [[EnforcedTrope favorably display their aggression and willingness to fight to the brass]] (executing the enemy was supposedly encouraged by officers to some degree in [=WW1=]) or [[ExploitedTrope exaggerated by their enemies to ensure that troops will fight to the death rather than surrender]], and executing the enemy could have simply occurred by the pragmatic reason that it was beyond the unit's ability to accept and control their enemy's surrender - though it is pretty certain all of these things did occur by some sort of extent.
* This is still true to some extent. Australia and Canada have some of about the best trained and equipped desert and arctic warfare specialists respectively in the world, simply because that's where so much of their territory is.
** It is commonly held that anyone who thinks about invading Northern Australia or Northern Canada is welcome to try; it is unlikely any non-native troops could ever hope to cope with those conditions.
* It's sometimes jokingly suggested that the British forged themselves a mighty world-spanning Empire because [[UsefulNotes/BritishWeather our weather]] is ''just that bad''.
** Alternatively, it was to get away from the [[HollywoodCuisine food]].
* Evolution works in the manner because if something wasn't tough enough it didn't survive to pass on its genes. This is especially apparent in oceans where limited resources created serious competition resulting in an evolutionary arms race with everything having to compete with and survive everything else.
* '''You'''. Your ancestors were the ones [[CaptainObvious that survived to be your ancestors]]. And given [[EverythingTryingToKillYou all the things that could have prevented that]], that is saying something. [[DareToBeBadass Go and do something awesome with that legacy.]]
** Before you were born, [[RaceForYourLove you had to beat]] a [[OneTrueSequence hundred million of your potential siblings]] to [[EggMacGuffin that egg]]. And that was with only half the chromosomes you have now.
* In the early days of the United States Navy, the entirety of their dedicated warship fleet were six heavy gun frigates. Because of the nascent nation's limited means, these six warships were designed to outgun anything of comparable size and outrun anything that outclasses it. The famous U.S.S. ''Constitution'' was one of these, and the "outrun" aspect is attested by their ability to run British blockades during the War of 1812, and the "Outgun" portion most exemplified by the famous U.S.S ''Constitution'' versus H.M.S. ''Guerriere'' naval battle. During the Barbary invasion ("The Shores of Tripoli" in the USMC Hymn) carried out because the US Government deemed coming to blows with the Barbary Pirates was less onerous than paying their tributes and ransoms, Ol' Ironsides was the main offshore bombardment asset in play. Today, the ''Constitution'' is the oldest commissioned warship still afloat[[note]]The Royal Navy's H.M.S. ''Victory'' is older, but she is permanently drydocked[[/note]], serving as a "Ship of State" for the US Navy.
* The reason veteran soldiers are generally superior to fresh recruits: they've survived the war.