[[quoteright:100:[[VideoGame/BillyVsSNAKEMAN http://static.tvtropes.org/pmwiki/pub/images/The_RNG.jpg]]]]
[-[[caption-width-right:100: [[Anime/CodeGeass The only people who should roll dice]] [[FinaglesLaw are those who are prepared to roll a 1]].]]-]

->''"If a statistician hands you a die insisting that 'any given roll has the same odds of rolling a one or a twenty', it means '''he's handing you a depleted die in the hopes of taking advantage of you'''. Don't fall for it!"''
-->-- '''Shamus Young''', ''[[http://www.shamusyoung.com/twentysidedtale/?p=1223 DM of the Rings]]''

A [[ArtisticLicenseStatistics statistician]] can tell you that properly generated random numbers will follow a discrete uniform distribution, giving you a roughly equal chance of rolling very good or very bad numbers. They may wax eloquent about how pseudo-random numbers are generated in computers, and how dice are wonderful randomizers. A good statistician will even disabuse you of the notion that a six sided die has a 1/6 chance to land on any one side; most dice are not built to that kind of precision. (Casino craps table dice are. They're also more expensive.) But it's going to be close to even distribution, even with a cheap die.

A gamer, either of the [[TabletopGames tabletop]] or [[VideoGames video]] variety, will tell you that this is all [[UnusualEuphemism a load of dingoes' kidneys]]. The characters that gamers play live and die on [[CriticalHit good]] or [[CriticalFailure bad]] rolls, and even if your dice are perfectly square and uniform, even if your game uses cryptographically strong random numbers, these numbers do not follow "distributions" or "probabilities." Instead, they usually produce whatever number you ''[[FinaglesLaw really didn't want]]''. A tabletop gamer may say that "the dice are trying to kill" him if he encounters a long set of bad rolls (e.g. broke every weapon he was carrying). Unless, of course, you know the proper way to placate the Random Number God: then the dice will smile upon you. Usually.

The name of this trope comes from VideoGame/{{Angband}}'s and VideoGame/NetHack's fanbases ([[TropeMaker coined in the Angband fanbase]], [[TropeCodifier spread by Nethack's]]), as a fanciful expansion of "RNG", for "UsefulNotes/RandomNumberGenerator"; both games are partially {{Luck Based Mission}}s, considering how many [[KilledOffForReal Instant Death]]s there are, and the players of both games have been known to build altars to the "Random Number God" or curse his/her/its name. Or both.

Some games try to cut out the nonsense by supplying their own LuckManipulationMechanic. This never works -- the Random Number God is not mocked, and it'll find a way to mess with you regardless. In RealLife or certain other situations, a TwoHeadedCoin can masquerade as a mere minion of the Random Number God up until TheReveal.

Sometimes called 'RNGesus,' especially when pleading for or celebrating a good roll, as in 'Praise RNGesus! It hit face!'


[[folder:Anime & Manga]]
* ''Manga/{{Saki}}'' proves that this trope applies to mahjong tiles as much as it does to dice. Nodoka [[AgentScully refuses to believe]] in players being "loved by the tiles" and such, but other players' freakish abilities to defy all probability when playing (as someone mentioned on the page, "how much can we make a statistician somewhere cry?") pushes her into FlatEarthAtheist territory.
* In ''Quick Start!!'', a 4koma about tabletop gaming group, a resident powergamer Karasuyama Sachi is on RNG's bad side, despite buying dice with equal distribution.

[[folder:Comic Books]]
* In ''ComicStrip/KnightsOfTheDinnerTable'', related to Hackmaster, a character was once beaten to a pulp for touching another gamer's dice. He was blinded by a cupful of soda and then was on the receiving end of a flying tackle. No one (except [[CommanderContrarian Sara]]) thought that this was uncalled for, as "that's one dice squirrel who'll think twice before touching another man's dice!"
** The attacker in that scenario was the 5'3" pencil-necked Bob Herzog, and the man who touched his dice was the 6'11" ex-marine Nitro Ferguson, and every time the event is referenced (the fight itself was [[NoodleIncident never shown]]) it is strongly implied that Nitro got hurt ''at least'' as bad as Bob did.
** In the strip, they even outlined a "dice cleansing" ritual, used to banish bad luck from the character's dice.
** Many dice superstitions are explored in this strip. Bob refers to his dice by name, keeps them segregated according to purpose and game genre. Dave refers frequently to having his section of the table "trained" the way he likes it for dice rolling. All of the Knights, even the sensible Sara, have dice rolling styles. But the most infamous incident had Brian and Bob "fame-rubbing" their dice on Gary Jackson's corpse (a "legendary RPG creator" pastiche of Gary Gygax and Steve Jackson) to charge them with good luck. This backfired because Gary, being dead, was obviously out of good luck (as Sara pointed out, someone who'd died in a plane crash couldn't have been very lucky to begin with). All the fame rubbed dice performed poorly in game play. (Or possibly because [[spoiler: that corpse wasn't Gary Jackson's.]])
*** The actual pen-and-paper role-playing game, ''HackMaster'' (written by the authors of the comic, naturally) enshrines a lot of these dice superstitions in its rules. Included on one page are prints of the signatures of the game's (fictional) creators, complete with instructions for how to empower dice with them.
* Averted in {{Foxtrot}}: During a TabletopGame/{{Monopoly}} game, Jason is shown holding dice in his hands and shaking them muttering "doubles... I need doubles...", but it turns out his strategy is [[HoldingTheFloor to do that until the other players forfeit]]. When playing [=RPG=]s, he has no particular rituals.

* ''Literature/LoneWolf'' has the dreaded Random Number Table, a grid in the back of each book numbered 0-9, that you have to use whenever you were in combat or were just trying not to get killed by some random. A few gave you bonuses based on Disciplines and equipment, but many more would gladly kill you if you didn't get a seven or higher. In many of those cases, ''not'' having that discipline would be even worse off as Lone Wolf would gleefully leap into deadly ambushes, activate ancient traps, fail to notice certain death curses or swallow poison whole. Giving you a 7-or-higher chance to live was actually the ''better'' path to follow in those events.
:: The thing is, the Random Number Table really WAS very much skewed and not really random, considering that the numbers in the grid are in a fixed position and you could more or less "aim" for sections of the RNT which were more likely to grant a favorable result. With practice, you could pull out a 0,1 or 9 anytime you wanted.

* [[TheRiftwarCycle Midkemia]] has two gods worshipped by gamblers: lady luck Ruthia, and mischief god Banath. They know to never invoke Ruthia's name to get good luck, because, the fickle lady that she is, might just give you the opposite of what you wanted instead.
* ''Literature/{{Discworld}}'' has an actual Random Number Goddess, but trying to curry her favour is not a smart move. The Lady (Always "The Lady", she will ''never'' come to those who use her name[[note]]Strongly implied to be Luck[[/note]]) does not appreciate being invoked -- gamblers who try to worship her directly always seem to die in strange and unlikely (not to mention unlucky) ways. It is said that she has a soft spot for hopeless cases, but relying on this would be a spectacularly bad idea.
* ''MalazanBookOfTheFallen'' has Oponn, the twins of chance (one increases your luck, and the other decreases it, but you don't know which you'll get if they bless you). One character unthinkingly named his sword Chance (and as a result has it blessed by them), and most every intelligent character he ever meets advises him to either break it or pass it to his worst enemy if his luck ever turns.
* In ''GodsDebris'', GodIsDead, having killed Himself at the moment of the Big Bang. However, He left behind matter ("God-Dust") and probability. Said probability determines how matter moves and evolves, effectively being the RandomNumberGod. Despite its seeming randomness, the probability's final goal is [[spoiler:God's complete reassembly]].

[[folder:Live-Action TV]]
* In a season 5 episode of ''BigBangTheory'', Sheldon makes all of his decisions on a 2d20 roll.

* Almost always averted in modern {{Pinball}} games. The end-of-game MatchSequence, where a player gets a free game if his score ends in the same digits as a randomly-generated number, is seldom truly random. Instead, most tables are set to distribute freebies based on various criteria, such as the number of players, a particularly low score, or occasional generosity (such as matching 5% of the time). The "random" nature of the Match is merely for show.
* Played straight in ''[[Pinball/BugsBunnysBirthdayBall Bugs Bunny's Birthday Ball]]'', where the [[GoldenSnitch game-breaking 50 Million]] shot is randomly enabled after the player blows out enough candles. And then there's the "surprise present" feature; at the end of a game, the winning player can have his highest score taken away from him and awarded to someone else.

[[folder:Professional Wrestling]]
* {{Conversed| trope}}, in that one of Leva Bate's finishing moves is called the {{critical| hit}} [[TabletopGame/DungeonsAndDragons confirmation]].[[/folder]]

[[folder:Tabletop Games]]
* In the back of the ''{{Hackmaster}} 2nd Edition'' rulebook, there's actually a list of various dice rituals that are prescribed for the game, including rubbing the dice clockwise for higher rolls and counter clockwise for lower rolls.
* ''TabletopGame/{{Warhammer 40000}}'' has an ''actual'', in-universe Random Number God -- he is the god of hope, ambition, change, fate and chance. The fact that he happens to be a [[EldritchAbomination Chaos God]] who liberally hands out [[CombatTentacles tentacles]] and [[TheCorruption other mutations]] to his followers both as [[SuperpoweredEvilSide boons]] and [[YouHaveFailedMe punishments]] should tell us something about the [[CrapSackWorld nature of the universe]]. As for the standard examples...
** A number of bizarre good luck superstitions have arisen in the 40K community, such as never calling missile launchers by their proper name (it has the word "miss" in it), the idea that painted models are luckier than unpainted models[[note]]Ork players don't count; their paint actually ''does'' change their units' abilities, by the rules.[[/note]], and the practice of occasionally muttering prayers to the Emperor. Never taken seriously, but often endearing.
** Don't ever say "anything but an X." The more important the roll is, the higher the chance that you will get that X. Most players have lost more games by saying "anything but an X" than by bad strategy.[[note]]If you need to say ''some''thing, and good sportsmanship dictates you usually do, saying "2's to [[ChunkySalsaRule squish]]" is usually safe-ish[[/note]]
** Also worth mentioning are the Chaos gods' chosen numbers. Chaos players used to get bonuses for fielding units of a certain size based on which god you were using. Slaanesh was 6, Nurgle 7, Khorne 8, Tzeentch 9, the idea being that the Chaos god makes the characters more lucky as long as they spend time in their chosen number. Modern versions of the game, for the sake of simplicity, have removed this rule.
** The 40K rule book advises players who are rolling large numbers of dice to take out the dice that failed and continue rolling the successful ones[[note]]each bullet is determined by 3 dice: whether it hit, how much damage, and whether the target's armor withstood, so squads with automatic weapons can expect to roll 30+ dice up to three times each[[/note]]. Players will tell you the ''exact opposite'': NEVER reroll the successful ones immediately afterwards, because they have just used up a good roll.
*** A player will say, "I never seem to roll as well as I just did." A statistician will say, "Well, duh. Regression to the mean. You just had a lucky break, so the same entirely random process is very likely to produce a lower value simply because most possible values are lower." Both are correct. The player will usually retort, "Whatever," and produce another fifty dice. 40K players ''always'' have enough dice, just never enough [[MoreDakka dakka]].
** Ork players are advised to use green dice for standard rolls ("green iz best"), red dice for moving through terrain ("coz da red ones go fasta"), and blue dice for critical rolls ("da luckiest"). [[TheHorde Buy in bulk]].
** It is also recommended, as the melta is one of the most powerful anti-armor weapons a troop can carry, that it never be referred to as such, as firing a melta weapon is an exercise in comedic inaccuracy. Simply referring to which model is firing should suffice. And never use Meltaguns against infantry. They might be great for blowing up tanks, but against infantry you're guaranteed to roll a 1.
** For the uninitiated, the game also sports something called Mathhammer, whereby anyone who can perform simple probability calculations about six-sided dice can figure out the expected results of any particular attack offhand. Naturally, anyone who engages in a quick Mathhammer calculation shouldn't do it aloud; you can't believe the [[StopHavingFunGuys superior chuckling]] of those who [[YouFailStatisticsForever don't understand probability]] if you're even one off in your calculations.
** Some Eldar players mutter prayers to Khaine, or to Cegorach if using Harlequins. Chaos players, meanwhile, invoke the Dark Gods, and Ork players just shout "WAAAAAGH" when shooting. Or charging. Or at random intervals.
* Another Creator/GamesWorkshop game, ''TabletopGame/BloodBowl'', features the RandomNumberGod directly, in both fluff and play. His name is [[IncrediblyLamePun Nuffle]].
** Neither thank nor curse Nuffle. [[HilarityEnsues You'll be punished either way]].
* In the {{Wuxia}} RPG ''WeaponsOfTheGods'', observed good or bad luck with the dice can be utilized as a game effect, discovering that the character is under a curse or blessing which can then be either increased to add actual bonuses or used to create a balancing effect of the opposite type.
** The system itself also features the River mechanic, designed to mitigate the influence of the RNG. You can take dice results out of a role and store them for later use, so if you make an awesome roll on a trivial task, or roll two sets when you only need one, you can set some aside and break them out later when you screw up something important.
* The Red Dragon Inn provides an in depth (and tongue in cheek) tutorial on how to [[http://www.rdinn.com/guild/69/how_to_make_the_dice_roll_high_numbers.html make the dice roll high numbers]].
* Referenced by name in HoylesRulesOfDragonPoker, where players are afforded infinite mulligans if they've angered the RNG.
* ''VideoGame/CardsAgainstHumanity'': It's not uncommon to put down a white card for the current black card, and then draw a card that would've suited that black card much better than anything else you have in your current hand.

[[folder:Video Games]]
* In ''VideoGame/CallOfDuty: World at War'' (as well as ''[[VideoGame/CallOfDutyBlackOps Black Ops]]''), the zombie killing "Survival" mode often involves a fair amount of spending credits earned by killing the aforementioned undead to take a spin on the weapon box, which awards a random weapon to the player. Since every gun in the mode can spawn there and the money is paid regardless of if you TAKE the gun, one must pray to the RNG.
** Black Ops has an equal amount of [=RNG=]'ing, both due to the Mystery Box, randomly dropped power-ups and a glitch that can randomly give a zombie insta-kill hits. Which still remains unfixed.
* This concept is taken to extremes in ''KingdomOfLoathing'', where the RNG is a conscious entity that has its own account and frequents the various chat rooms. Those who please the RNG in some way may find themselves "Blessed by the RNG", whereas those who annoy it (especially by begging for a blessing) may find themselves "Cursed by the RNG" (both of which are active character effects). Because [=KoL=] game mechanics rely heavily on random number generation, and because [=KoL=] effects are rarely explicitly defined, there is still a significant debate over whether or not the Blessing and/or Curse actually affect a player's RNG-based "luck" in the game, or if it's just a red herring.
** A player may also be "Blessed by The RNG" by sending a gift package with an 8-ball, and a look in The RNG's display case may reveal other effective sacrifices.
** One particular area that makes players rage to the RNG: the F'c'le. In order to earn Pirate Fledges and be able to access the Obligatory Pirate Cove without wearing fairly weak equipment (the Fledges themselves are actually pretty strong), you must defeat three specific enemy types in this area, pick up their random drops, and use them. Every [=KoL=] player can regale you with stories of spending hundreds of adventures praying for the right enemy to show up, or, alternatively, having all three enemies show up in turn and give up their items in a row. The RNG in the F'c'le is an ''extremely'' fickle godling, and no one can predict its mood on a given day.
* In the {{Roguelike}} communities where [[TropeNamer the term originated]], finding a very good item early in the game is a sure sign that the rest of it is going to be a hellish struggle against the wrath of the RandomNumberGod. It's given you your one good thing, now it's going to do its damnedest to kill you.
** The ultimate item in this is an Amulet of Life Saving, which effectively gives you an extra life (in Roguelikes, if you die, that's normally it -- your ([[SaveGameLimits one]]) save game is erased). If you find one of these early, rest assured the game is going to maneuver you into a situation where even instant resurrection will not help you. After all, if something is tough enough to kill you once, it can probably do it a second time... Paradoxically, "lucky finds" like this that should improve your chances of survival will just make players incredibly paranoid and even ''more'' cautious.
** Added as a character in ''{{TOME}}'' (and its parent game, ''ZAngband''). Random Number Gods are weak, annoying, fast multiplying monsters that drop decent loot -- and cause confusion.
* In some roguelikes, the random number generator is known to get locked into generating the same number repeatedly for an extended period of time more often than probability would suggest it would happen, so seeing a 1.7% chance happen 10 times in a row is not unheard of, especially when you are on the wrong end of it. Ouch. Of course, this is normally because, when you're on the ''right'' end of it, you don't need a second chance. ''Your'' critical hits are basically kills, but when [[EverythingIsTryingToKillYou Everything Is Trying To]] [[DeathOfAThousandCuts Nibble You To Death]]...
* Starting characters in ''VideoGame/{{Angband}}'' and its offshoots are very dependent on the RandomNumberGod smiling favorably due to the lack of abilities and equipment. Character deaths on the first few floors happen very often, requiring a few do-overs before being able to finally survive.
* Players of ''[[MagicTheGathering Magic: The Gathering Online]]'' revere Grog, Goblin Shuffler.
* We of the ''FinalFantasyTactics'' online simulator Super Tact pay our sacrificed goats to her most revered Random Number Goddess.
** Also from the ''FinalFantasyTactics'' main series, it shows you the odds that your attacks will hit before you make them. However, anyone who has played the franchise will tell you that these odds are not true, because anything less than an 85 will not hit. Ever.
* Anyone who has ever played ''FireEmblem'' will curse his name. No exceptions. Just for those who don't know, FinalDeath is in place for all units. Think you can take that guy who has only a 1% chance of landing a critical hit? Think again. In some games, the sequence of random numbers generated after a save is always the same, allowing for a degree of predictability. Proper manipulation of the RNG is key to any ''Fire Emblem'' {{Speedrun}}.
** Various [[WildMassGuessing theories]] point to the RNG being a Random Number ''Goddess'', specifically Anna, an NPC (one who has appeared in every game to date [[note]]except for ''[[VideoGame/FireEmblemAkaneia Gaiden]]''[[/note]], sometimes with her husband Jake... who ''always'' has above-average stats.) She's something of a SeriesMascot.
*** It's probably vindicated by ''[[VideoGame/FireEmblemAwakening Fire Emblem Awakening]]'' as [[spoiler:she appears as the final boss of the secret path in the hardest DLC chapter, Apotheosis. She comes with stats that no class could ever achieve (even with Limit Breaker), a forged Spear and Brave Lance, and the skills Dragonskin, Aether, Vantage+, Counter, and RIGHTFUL GOD.]] [[MemeticMutation Pick a god and pray indeed.]]
** ''[[VideoGame/FireEmblemTellius Path of Radiance]]'' actually features an instance where the RNG can be made to work for you, instead of on his own whims, with the Bonus Experience. Got a character that really needs consistent growths in certain stats? Simply save your game right before giving them the bonus experience, the only time when you can consistently A) save your game, and B) have a character gain a level without any other factors at play; if you didn't like the stats they gained, no problem! You can reset the game and try again as many times as you want, until the character gets the desired stats. And then the sequel, ''Radiant Dawn'', allowed ''quick saving'' (except on Hard), so you could do this same thing whenever you wanted, in battle! Foolish, Random Number God. Foolish.
** Quick saving was also present in ''[[VideoGame/FireEmblemJugdral Genealogy of the Holy War]]'', though it had the "Use Exact Same Strings" method, as well as a bug would cause the game to run out of Numbers during Arena combat, resulting in level-ups with no stat gains.
* The RNG manifests in ''VideoGame/BillyVsSNAKEMAN'' as a monster that players in a village (read: clan) can fight. While all other monsters of that class have accurate HitPoints displays, the RNG has nonsensical numbers or words to represent remaining and total life. It also shows up during [[HolidayMode The Festival,]] where it runs a game where you roll ten dice; anything higher than a one gets you an obscenely valuable item. [[CaptainObvious The item cannot be obtained there because you only ever roll ten ones.]] Getting it actually requires completing an entirely different quest.
** Players who have become aware of higher-dimensional spaces may start to briefly encounter the RNG in other locations, and one of the more traumatic experiences during a quest is briefly seeing it in its true form.
* In ''VideoGame/WorldOfWarcraft'', it's customary to use the /roll command a few times before rolling for a specific piece of equipment to please the RandomNumberGod and to get the low numbers "[[YouFailStatisticsForever out of the way]]". In addition, there are persistent (but frequently debunked) rumors that the game seeds the random number generator according to specific criteria, including, but not limited to, the raid leader, the first person entering the dungeon and/or the number of damage-over-time spells ([[http://www.youtube.com/watch?v=HtvIYRrgZ04 more dots!]]) on the boss.
** That's ridiculous. Everyone knows that the dice will only favor you if you A) contributed the least of anyone to the party/raid, B) can't use or shouldn't be using the item in question, or C) have someone else present who has waited for the random drop for months. These effects are cumulative, and if all three are true you're almost guaranteed to win. The RandomNumberGod of WoW is a sadistic bastard.
*** It is possible to ''increase'' the odds of a desired gear piece to drop by spending a lot of gold on ridiculously expensive gear enchantments or gems to enhance the piece you desperately want to replace, or to buy a lesser temporary substitute at the auction house (or the crafting materials to have one made by a blacksmith). Ask any player, everyone has a tale of spending a fortune on a piece of gear only to have a better one drop magically in their hands not one day later.
*** It's also not unheard of for someone to get an upgrade on their first try as long as another member of the party has been attempting to get a drop from the same boss for a long amount of time. It's not just sadistic, it's pure evil.
*** A needed upgrade for a raid member will often drop week after week in their absence, only to never be seen when they do show up.
**** Or worse, an item that no one can use after the first week will drop every. Single. Week.
** God help you if your prep roll yields a 100 or similar high value; that was the only one gifted to you by the [=RNG=] this month.
*** As a tank, God help you if your prep roll was over 15. Tanks have by far the worst luck rolling on anything, and you aren't likely to top 15.
**** Doubly so for warrior tanks, who are notorious for losing a roll on the same piece of gear multiple consecutive times, by one point.
**** Part of that is also that tank specific gear is also the least likely to drop in any circumstance, and with the random dungeon finder, they have the easiest time getting into a dungeon.
** The developers are equally sadistic with this. Two of the Achievements involved having to get 100 on rolls to Need or Greed loot (once the system was redesigned to distribute loot drops automatically). It can take as long to get those to come up as specific, desperately wanted gear.
* ''{{Suikoden}}'' has trouble with this at times. There's a cup shuffling game where the dealer always follows a specific pattern every time you quit and play. However, there's another game that involves throwing three die. Despite the fact that the odds of getting very good rolls (three of the same number other than one, or a straight of 4-5-6) or very bad rolls (all 1's or a straight of 1-2-3) should be low, you'll find that you and the computer will get these combinations very frequently. Murphy's Law of course will turn what should be a 1/216 chance into 1/3. Also, a ground rule is that you must roll something valid in three turns (i.e., you automatically lose if you roll three "no scores"), the computer will always roll something valid on the third turn (even if it's one of the dice going out of bounds).
* The poker minigame in ''VideoGame/TalesOfVesperia'' has a rigged RNG. It's very easy to win once, but if you try to double your earnings, the RNG makes your life horrible. The higher the value of your hand is (i.e. straights, flushes, full houses, etc.), then the more the RNG will screw you. If you bet 'Low' on a King or Queen, then there's a very high chance you'll get an Ace or Joker. Vice versa applies to betting 'High' on threes or fours. And even if you have a relatively low value hand (Three of a kind, two pairs), the RNG screw up kicks in at about the fifth time you want to double your earnings. Roughly 90% of the time, you'll lose by betting low on Kings and Queens, while you'll have a 50% chance if you bet high.
* Anyone who has ever played ''EverQuest'' and attempted to level tradeskills beyond a certain point knows that the RNG is a spiteful beast that hates you. There is a reason the premier crafting forum has the appropriately named [[http://mboards.eqtraders.com/eq/forumdisplay.php?26-Primal-Scream-Room Primal Scream Room...]]
* Players of ''CityOfHeroes'' will notice that, after extended periods of time, you will miss with several attacks in a row despite your accuracy hovering from anywhere between 75% to 95% (the highest possible). Clearly the Random Number God at work. As opposed to, say, you just having an unlucky streak of rolls which is nearly guaranteed to happen the longer you play the game. Nope, the Random Number God definitely woke up with a hangover that morning and decided to take it out on you. It ended up being such that the developers turned the RNG into a quasi-RNG: If the random distribution did not meet the ideal after a certain amount of time (generally meaning that a player missed a lot), it would force favorable results until it did.
* SaveScumming at the dice minigame in JadeEmpire results in the Random Number God coming to blow off the GM's head.
* The ''VideoGame/MonsterHunter'' fandom has come to the conclusion that the series has a sadistic, psychic, "desire-based" RNG for determining how often a really rare item RandomlyDrops, also known as the [[http://www.gamefaqs.com/boards/943655-monster-hunter-tri/54801743 desire sensor]]. It ''will'' skew the odds out of your favor if you really want something, and the only way to end your curse is to not want it. You can't ''act'' like you don't want it, you have to ''actually'' not need it; the system is immune to reverse psychology. So if you spend hours farming the same giant monster for its armor plating, you may go through fifty corpses without seeing one, but you'll end up swimming in the stuff once you give up and move on to a different goal. The only other way to appease it ''may'' be petting the pig.
** Given that the engine knows the characters' profiles, quests, recipes and any discovered players' paths, the implementation of a sadistic "you'll always get stuck with [[TwentyBearAsses only nineteen bear asses]]" drop routine is easy. In fact, it would be a usual semi-random drop with reversed adjustments. So the question is whether it's really that random, or not.
* ''VideoGame/FTLFasterThanLight'' and its RNG can result in an unwinnable game if you are unlucky enough to go through the entire game without getting a set of good weapons.
* Due to the nature of the makers (and fanbase) of ''VideoGame/DragonFable'' the RNG is nicknamed the Rude (or Reall) Nasty Gnome. He sits on a floating pile of all of the gear in the game and throws items at heroes who finish quests. Those heroes that 'amuse' him, get a better item thrown at them (albeit faster).
* In Franchise/{{Pokemon}} games, there is a chance of encountering a "Shiny" Pokemon. This is actually just a normal Pokemon with a recolor and a sparkle animation when it enters combat, but they are highly sought-after nonetheless, just because they are so extraordinarily rare. How rare? The odds of encountering a shiny Pokemon in a random wild battle is approximately 1/8192. Couple that with the odds of capturing a Pokemon you've just found, and you've got one frustrating challenge. If you ever see a player with a shiny Pokemon, you can be sure they've been blessed by the RandomNumberGod. Or they're cheaters. Or they got it at an event. [[VideoGame/PokemonGoldAndSilver Or it's a red Gyarados.]]
** Unless you're playing ''{{VideoGame/PokemonXAndY}}'', where the rate appears increased and people are getting them all over from Friend Safari,Hordes or chain fishing...
** Players have managed to reverse-engineer the random number generator, and by methods that are [[LoopholeAbuse technically not cheating]], including precisely timing button presses and setting the Nintendo DS to a specific date and time, can significantly increase their chances of getting a Shiny Pokemon and/or one with the best possible stats.
*** However, you would still need to have a few Shinies to make this work, or you can read your save file, because one of the factors required to get a shiny is your "Secret ID," which cannot be found in the game. Thankfully, Shinies are the mainly the only thing that requires that number.
*** And that is now being exploited by people who use another software to help others find that code. Then, all that's needed is to use that method, determine the shiny code each egg has, and find someone on the 'willing to hatch' list whose game id matches the egg's code,and the result is a guaranteed shiny.
** Pokémon is ''made'' of this trope. There's the randomness of getting the Pokemon that you want (have fun finding ones with lower than 1% encounter rates), and the randomness of Natures and [=IVs=] on top of that (and as mentioned above, the extremely rare chance of getting a Shiny). Once you have your Pokémon and use it in battle, you get to enjoy the RNG of critical hits and secondary effects of moves, like flinches or status effects, as well as the RNG of hitting at all. There's even an RNG for attack damage, which varies between 85% and 100% on a bell curve. Get unlucky and have it hit for the low end, and you might have missed a crucial KO.
*** High level AI opponents such as the gym leaders are eternally blessed by the RNG. If there is one thing they can't stand, that is you scoring a perfect, flawless win against them. So what if you trained your Pokémons to be ten levels above the next gym leader's average Pokémon level? Once you start to one hit KO the gym leaders Pokémons, suddenly they pull out somebody knowing [[http://bulbapedia.bulbagarden.net/wiki/Metronome_%28move%29 Metronome]], which "randomly" selects [[http://bulbapedia.bulbagarden.net/wiki/Tri-Attack Tri-Attack]] (something that has a 20% chance to freeze) from over 550 moves, which in turn freezes your Pokémon instantly. All this just because they don't have an one-hit KO move or an ice-type move to freeze you but you must lose at least one Pokémon to them. Calculate the odds of this happening exactly when you want it to and you realize who is the [[TheComputerIsACheatingBastard cheater]] here.
*** Some competitive communities, such as {{Smogon}}, try to keep the effects of the Random Number God to a minimum, through means such as banning items like Brightpowder and moves like Double Team and Minimize that rely ''solely'' on RNG to work. The mindset is pervasive enough that many battlers in these circles will go so far as to ''apologize'' to their opponent if RNG starts to favor them, such as with a crucial {{Critical Hit}} or an attack with a small chance at a secondary effect getting that effect (ie. If a Thunderbolt induces paralysis in the target).
** And may Arceus help you if you encounter a [[http://bulbapedia.bulbagarden.net/wiki/Graveler shiny]] [[http://bulbapedia.bulbagarden.net/wiki/Beldum Pokemon]] with a [[ActionBomb penchant for]] [[SuicideAttack suicide...]]
** The Sinnoh games gave players a possible means to fudge the shiny system-- the post-game Pokemon Radar can be used to "chain" repeat encounters with a specific kind of Pokemon. The longer your "chain", the odds of finding a shiny Pokemon slowly increase, until it caps at 1/200 (after about forty Pokemon). The Poke Radar also has a unique animation for detecting a wild shiny Pokemon.
** And then, there are reportedly various rituals that can be used to increase the chance of successfully catching a Pokemon after a Poké Ball is thrown, such as timing pressing the A button as the Poké Ball closes and every time it shakes, mashing buttons, specific taps on the DS touch screen, etc. [[spoiler:They're found nowhere in the games' code.]]
*** [[http://www.vgcats.com/super/?strip_id=8 Red pressed A+B+Down!]]
** To a lesser extent, Voltorb Flip from the non-Japanese versions of ''[=HeartGold=] and [=SoulSilver=]''. Because it is both skill-based and luck-based, you can win big, but you can (and will) more easily win very little. The game is much like a cross between Picross and Minesweeper: you have a five-by-five grid of tiles, and each row and column contain multiplier cards or Voltorbs. If you get a multiplier card, your current coins are multiplied by that number (If you haven't won any coins yet, you simply get coins). If you win, you advance a level and can win more because there are more multiplier cards. The catch is that you can just as easily land on a Voltorb, which not only makes you lose all the coins you got in that particular game, but also ends the game altogether, ''and'' sends you back to an earlier level based on how many multiplier cards you flipped; if you're unlucky enough to lose right off the bat, back to level one you go. It's not entirely luck-based, but it's still far easier to lose your coins and/or end a long streak of wins on an unlucky flip than to actually start off said long streak of wins.
* Mr. Game and Watch from ''VideoGame/SuperSmashBros'''s most powerful attack relies on randomness, and varies from ("1") a weak hit to ("9") blasting your opponent across the screen, even with little damage from the start. This unpredictability is much of why he is considered a lower-tiered character by the competitive fanbase.
** To be fair, most players turn off the items for any competitive match because the RNG loves nothing more than waiting until you and your rival are at one life each, then spawning a [[ActionBomb Bob-Omb]] or an exploding crate right in front of you at the very moment you attack.
* The FourX game ''SwordOfTheStars'' was practically built around this trope. In addition to the usual randomly generated maps of most FourX games, the game also semi-randomly spawns various "menaces" unaligned with any race that range in threat level from GoddamnBats to ThatOneBoss, and even randomizes the ''tech tree''. Some techs are considered "core" and guaranteed to be available for research to all races, most have a random chance of appearing at all for each race (with probabilities ranging from 0% to 100%, depending on the race and tech in question), and some are exclusive to particular races, and some of ''those'' aren't guaranteed to be accessible to their race in every game.
* ''GodHand'' can be bad about this. Low on health and need a pick-me-up fast? The dice often aren't on your side.
* Want to heal your critically hurt union in''TheLastRemnant''? Better damn well pray that the AI generates the heal option for you on your list of unit actions for that round.
* Get enough assassins in ''[[TotalWar Medieval Total War II]]'' or its predecessors, and it's easy to see the chances of success the computer gives you are not very accurate. Having a less than 30% chance of success means, more often than not, even eight assassins with that percentage will fail, even if attacking enemies from two separate nations. There seems to be lucky and unlucky turns, as if one assassin succeeds with a 23% chance, there is a good chance others will too, and the reverse if one with an 80% chance fails.
* ''VideoGame/{{Civilization}}'' uses an RNG to resolve combat, among other things. On account of the way the system worked, this led to the famous [[RockBeatsLaser Spearman Defeats Tank]] meme within the community. The problem was fixed in Civ II, but then III and IV screwed it up again (though not quite to Civ I levels).
** ''Civilization IV'' and ''V'' at least give you the option to keep the same seed for the RNG between game loads but only for the entire match. With the same seed, you can effectively predict the future. With different seeds on each load, you can [[SaveScumming save scum]] all you like until something good happens.
* In ''VideoGame/NexusWar'', "The RNG hate my/your guts" became a bit of a [[MemeticMutation meme]] on the forum, generally in relation to searches or hiding (i.e if you tried to hide with more than 10 AP left or REALLY needed to find a supposedly common component you would fail) more than combat which was PvP.
* The Facebook game Empires & Allies by Zynga has this trope due to how critical hits occur. Critical Hits and more importantly Critical Kills give more loot, exp, give Ore and often Energy. They are thus VERY desirable. Players have come up with a theory that aiming for "sweet spots" on various targets grant a much higher than normal chance for a critical. This theory has not been conclusively proven or disproven.
* The ''[[VideoGame/{{X}} X-Universe]]'' games rely on an RNG to determine such things as NPC cargo and equipment, what enemies spawn and where they travel, and especially BoardingParty casualties. Praying to the RNG has become a RunningGag on the forums.
* In ''WizardryLabyrinthOfLostSouls'', you will receive a random number of bonus points to allocate to your stats upon character creation. This can be as low as 6 to (allegedly) as high a number as 47. Exiting, then reentering the character creation screen rerolls this number. This often leads to character creation taking '''hours''', not because of many customization options (you only choose your character's name, race, gender, alignment, stats and class), but because players keep exiting and reentering character creation in hopes of getting a higher amount of bonus points. This is compounded by the fact that lower numbers occur far more often, while numbers get rarer the higher they get, so only the truly blessed ones among us will ever see a number in the forties.
* In ''VideoGame/UrbanDead'' nearly all actions are luckbased and thus dependant on the RNG. People who have wasted their entire day's worth of AP on missed attacks or uselss searches will understand how frustrating this can be.
* In ''VideoGame/XCOMEnemyUnknown'', the RNG will actually ''help'' players of the Easy and Normal difficulties, although He/She only provides subtle assistance in trickier dierolls in Normal. The kid gloves come off in Classic and Impossible, though. Expect to be ''furious'' about missing 80% chances to hit, or flubbing that Rocket Launcher shot.
** The expansion pack, ''Enemy Within'' offers a "SaveScumming" option - the original would have the RNG result occur every time (Missed that 90%? It will ''always'' miss when taken in that turn order), while this option rerolls it on the RNG.
* ''{{RuneScape}}'' has its fair share of skewed probabilities, but a game moderator once memorably said "the random number generator gods are fickle and bow not to mortals".
* ''VideoGame/TheSimsMedieval'' gives you "success odds" of certain tasks your Sim can perform, but "medium" is more likely than not to result in failure on difficult things. Never try, for example, picking the lock on the stocks with your Spy when the odds are only medium. You ''will'' get caught.
* All players of the ''VideoGame/MassEffect3'' multi-player know that the items store is governed by a Random Number God. Say for example that you prefer to play snipers, so of course you want to unlock some powerful ultra-rare sniper rifles. Maybe you've really got your sights set on that Black Widow. Of course, you'll get shotguns. You'll get assault rifles. You'll get [=SMGs=]. And if you do get a sniper rifle, it'll be the Incisor. And at some point, you'll have all your weapons maxed out but the Black Widow is still only at level 2.
** This is [[LampshadeHanging lampshaded]] by one of the random conversations you can overhear in the Citadel DLC, where an N7 Fury (a biotic that favours light weapons) is arguing with a requisitions officer that keeps trying to give her upgrades to a very heavy shotgun.
--->'''N7 Fury:''' You're the reason we're losing this war!
* The ''VideoGame/RuneFactory'' fandom has been citing the Random Number God quite often with the release of ''VideoGame/RuneFactory4''. Whether or not you can successfully confess to a person, when you will see all the event you need in order to propose or be proposed to, and when you will get access to the final dungeon of the game are all entirely random. You might be able to clear the entire plot and get married in the first few seasons you play through, and you might spend five years waiting for that last event you need to activate.
* The RNG of ''VideoGame/WorldOfTanks'' is frequently cursed by players for things including, but not limited to, map selection[[labelnote:*]]Certain maps being detested by segments of the player base, or very unfavorable to some vehicles[[/labelnote]], game mode, shot deviation, shot penetration, and damage[[labelnote:*]]The last two frequently resulting in vehicles surviving shots that "should" have destroyed them[[/labelnote]]. The "matchmaker" that assembles random teams comes in for a double round of cursing for assembling teams that are seen as wildly imbalanced, either in player skill or vehicle lineup.
* ''VideoGame/FinalFantasyXIV'' is BRUTAL with RNG when it comes to crafting. Crafting high quality items can require an insane amount of luck (it's completely random on how often your next move can be used on a turn with an excellent condition), even if you try to set up the odds in your favor as best as you can. If RNG doesn't favor you, you'll fail your crafting and lose all the materials that were used for it.
** The Atma quest lines are just as bad. To get your foot in the door for powering up your InfinityPlusOneSword, you must hunt down 12 Atma items. Said items have a supposed 2.5% chance of dropping after each event you clear, You can get a few Atmas in a few hours or possibly ''nothing after several days''.
* The hit Japanese webgame ''VideoGame/KantaiCollection'' has this bad. How bad? The initial access to the game is dealt to you ''via lottery''. After going in, the RNG continues to hinder you as you play, ranging from misses and critical hits[[labelnote:*]]Bad, since even the heaviest ships has a [[GlassCannon disproportionate ratio of hitpoints versus damage]], and even normally-weak enemy destroyers can still land a critical hit on your battleships costing them half their hitpoints, especially in night battles[[/labelnote]] to item-crafting and the constant stream of NAKA-CHAN DAYO~[[labelnote:*]]When you craft ships, the odds are skewed towards certain classes of ships due to the sheer size of variety; Sendai-class light cruisers (Sendai, Jintsuu, and Naka) are particularly detested for being extremely common, although they are by no means weak/useless[[/labelnote]]
* [[SpeedRun Speedrunners]] endlessly bemoan the nature of random number generators. For longer speed runs, and depending on the game, a lot of RNG rolls can be encountered on an ideal fastest route through a game. Manipulating a game's random number generator (to influence item drops, the movement of [=NPCs=], etc.) is virtually impossible in most games played in real time (with rare exceptions), so your highly optimized, world-record pace run could come crashing down just because the game says so. In a hobby as repetitive as speedrunning, where you could spend hundreds or thousands of attempts trying to nail all the tricks in your route, this can be very demoralizing.
** Tool-assisted speedrunners, on the other hand, have the benefit of being able to control inputs frame-by-frame and check memory values. They can reliably influence a game's random number generator, making it look like the game is conspiring to have them go as fast as possible, both by having all enemies and NPCs be at the right spot at the right time and if there's a RareRandomDrop that speeds up the process, you can bet the run gets it from the first possible enemy.
* ''Franchise/ShinMegamiTensei'' games up until ''VideoGame/DevilSurvivor'' has the [[FusionDance fusion]] mechanic. You demon/[[Franchise/ShinMegamiTenseiPersona Persona]] can inherit skills from the previous demons you used in fusion, but what skills you actually got were randomly generated. Many players have bemoaned how long it takes for them to get the skills they want by selecting the demons, rolling, failing, and rerolling over and over again causing a lot of FakeLongevity. If the RNG is especially cruel, the game may decide to give the player a Fusion Accident, resulting in a completely different demon than the one they tried to make, making all those rerolls [[ShaggyDogStory ultimately for naught.]] Randomly inherited skills was thankfully dropped as a mechanic in later games, though Fusion Accidents can still happen.
* Earlier versions of ''VideoGame/{{Tetris}}'' are infamous for this. Need an "I" to get a Tetris? Not on your life. Have a bunch of garbage to clear out? ''Now'' they show up! This is why ''VideoGame/TetrisTheGrandMaster'' uses a tailored randomizer that biases against dealing recently-chosen pieces and modern ''Tetris'' games use permutations of the seven tetrominoes.

* [[http://archive.gamespy.com/comics/dorktower/images/comics/dorktower636.gif This]] DorkTower strip was the beginning of an arc about scheming dice that started behaving only when the cats got a hold of them.
* Sometimes, the power of the dice can get a little [[http://nodwick.humor.gamespy.com/ffn/index.php?date=2005-06-23 out of control]]. Efforts at appeasing the dice may [[http://nodwick.humor.gamespy.com/ffn/index.php?date=2005-07-12 meet with failure]].
** That was stupid. [[RandomNumberGod They rolled out all the 20s first.]]
** A strip in ''Webcomic/RealLifeComics'' parodies the idea of [=THAC0=] where the main character misses a stationary enemy that wasn't focused on him because he rolled too low to hit it.
* There's a sort of DoubleSubversion to this concept, detailed in the annotations to [[http://www.darthsanddroids.net/episodes/0099.html this]] ''DarthsAndDroids'' strip, which involves "rejecting that superstitious nonsense" and instead using the laws of probability distribution:
## Take 1000 or so 20-sided dice.
## Roll each and every one of them ''once''.
## About one-twentieth of these will have rolled 1s. Take these fifty-odd dice, and roll each of them again, ''once''.
## Two or three of these dice will now have rolled 1 twice in a row. Statistically, the odds of rolling the same number three times on a 20-sided die is 1 in 8000, so now these dice have the 1s "rolled out of them"
## Place them in a special padded container so that they can't roll around, and you may now safely bring them out in emergencies for use for a die roll in which you ''really don't'' want a 1.
** This is of course patent nonsense; no matter how many times in a row you get a 1, the odds of the ''next'' roll getting a one are always 1 in 20, even if it seems "overdue" for a different number.
*** It's not just nonsense, it may be totally backwards. If a d20 rolls two 1s, which is a 1 in 400 occurrence, then the dice might be flawed, and rolls 1 more often than it should.
** ''DarthsAndDroids'' also goes as far as to [[LampshadeHanging Lampshade]] the trope with a link in the annontations of the strip mentioned above that links to this very page.
** The Random Number God will smite thee, unbeliever.
** [[http://www.darthsanddroids.net/episodes/0195.html This strip]] demonstrates this strategy in action: The prerolled die yields a natural 1 but the RandomNumberGod's true believers don't waver. They reason it will simply be ''even more lucky'' next time.
* ''FullFrontalNerdity'' carries this to a ludicrous extreme when Lewis attempts to dispose of a 'cursed' die that can seemingly only roll 1s. The die rises from the grave and the curse is so strong that every random number generation device in the world becomes incapable of generating any number other than 1.
* In ''DubiousCompany'', after the heroes rescue Future High Priestess Sal, they return her to the ''[[http://dubiouscompany.com/comics/2007/08/19 the Temple of Phred]]''. Bask in its neon glory.
* [[LampshadeHanging Lampshaded]] [[http://search.dilbert.com/comic/Random%20Number%20Generator in this]] ComicStrip/{{Dilbert}} comic strip when he's touring a layer of hell known as Accounting.
* In the ErfWorld comic intermission, a Luckamancer [[DiscussedTrope discusses]] the [[http://www.erfworld.com/2011/11/inner-peace-through-superior-firepower-%E2%80%93-episode-008/ mechanics behind luck-manipulation]] with a young Wanda :
-->''"Now here's an important thing, though," said Clay, pointing at the die. "Where did those 4s come from?"''
-->''Wanda looked down at the little brown enchanted pyramid and shook her head. "From you. You cast upon the die."''
-->''Clay grinned slyly. "So you're saying my juice had a physical effect on the way the die rolled."''
-->''"Yes and ''no''," said Clay, grinning more broadly now. "It's not a direct effect, you see? The 4 is a Number. It had to come from somewhere."''
* The ElijahAndAzuu sequel presents a character who actually manages to beat the Random Number God. She has a lucky 20-sided die, and due to residual subconscious magic the die is literally unable to roll a 1, even when other characters use it.

[[folder:Web Originals]]
* A ''College Humor'' sketch about VideoGame/{{Tetris}} called "[[http://www.collegehumor.com/video/5767906/the-tetris-god The Tetris God]]" involves the eponymous character manually choosing which piece will be next.
--> ''"Thou art a '''cruel''' and '''angry God!!"'''''\\
'''''"LINE PIECE!"'''''
* Ribbon of ''/[[ImageBoards tg]]/ [[http://1d4chan.org/wiki/Ribbon#.2Ftg.2F_Explained explained]]'' series [[http://1d4chan.org/wiki/File:Tge51.jpg explains]].
* Often invoked on ''WebVideo/{{Tabletop}}. In the ''Elder Sign'' episode, Creator/WilWheaton claims that the dice are trying to kill him. [[spoiler:They succeed.]]

[[folder:Real Life]]
* Cards. When you've already drawn the ones that are good for you, they're not in the deck any more. Notions about the RandomNumberGod seem to grow out of expecting dice to behave like cards.
* There are some calculations scientists perform that require truly random numbers, such that the slight predictability inherent in a computerized system is too large. For these cases a "True Random Number" generator can be purchased, which is effectively a small radio telescope tuned precisely to the frequency of the Cosmic Microwave Background radiation, as produced by the Big Bang.
** Radioactive isotopes can also be used - set up a Geiger counter and a numeric counter, then stop the counter whenever the Geiger meter goes "beep". The time between successive radioactive decays is random, so your numbers are random.[[note]]For those wondering about Half-Lives, what's normally done is to measure only whether the time between decays is more or less than the previous one, and use the sign as the resulting bit[[/note]]
*** http://www.fourmilab.ch/hotbits/ serves up fresh hot discarded random bits on demand, using radioactive decay.
** Noisy diodes are also truly random, and as a benefit for computers, binary.
*** For some delicious ParanoiaFuel, ponder upon what may happen when a suitably tech-savvy adversary arranges for it to be irradiated with strong radio waves.
*** Similarly, overdriving a transistor into overheating so you can read thermal noise from it.
** http://www.random.org/ generates random numbers using atmospheric noise.
** Actually getting a random number out of a truly random source is far from trivial in itself - you have to build a device that doesn't introduce any bias.
* As [[http://www.youtube.com/watch?v=bR2fxoNHIuU&eurl=http://grognardia.blogspot.com/2008_11_01_archive.html this]] video explains, cheap dice have dull edges because they were polished in a rock tumbler. The resulting imperfections change the die's center of gravity and make it easier to roll over some edges than others. So there is a scientific explanation to this phenomenon, and a way to prevent it.
** It also makes reference to one of the classic ways con artists can rig games: "shaving" the edges on a die (usually a casino die, since they have sharp edges to begin with). You trim off a tiny bit on the edges of whatever's opposite the side you don't want to land on. So for example, if you don't want to roll a six, you'd shave the edges of the one face. The die expends less energy rolling over the shaved edges, which skews the probability ''way'' below 1/6. (Incidentally, if you find an ''actual'' casino die that's been shaved, you could be rewarded by the state gaming commission. [[SeriousBusiness They take fair odds seriously.]] Outside of a casino, though... just remember the page quote.)
** Another common method of messing with die odds is to cook them. You take your plastic die, put it in the microwave with the side you want to show face up, then nuke it for a couple of seconds, no more than five. The nuking causes the plastic to melt downwards a bit(thus making the die more likely to stop on that edge, since it's heavier). Done right, it's almost undetectable at casual inspection.
*** And knowing that means that your GM is justified in confiscating your dice if they seem to be unusually 'lucky'.
* Most computer software use a [[http://en.wikipedia.org/wiki/Pseudo_random_number_generator Pseudo random number generator]] Often, a programming language's library will provide it, but for early games and applications, bugs in the implementations of pseudo random number generators caused biases. C's built-in random library is actually notable for allowing programmers to use it incorrectly and introduce biases to the numbers generated by it. Problems with how the random number seed is picked can also cause the numbers to be predictable.
** Since random number generators are used by many security applications, their predictability can lead to [[http://en.wikipedia.org/wiki/Random_number_generator_attack serious security vulnerabilities]]. Which makes computing with serious security need another area of use for the aforementioned true random number generator devices.
*** Then again, if it can't get truly random numbers, any decent security application will use a ''cryptographically secure'' generator[[note]]One whose future outputs are impossible to predict from the outside, and whose past outputs are impossible to guess even if the generator's internal state is known.[[/note]], not the run-of-the-mill ones provided by a language's standard libraries.
** Although implementation issues with random number generation itself have been largely averted with more modern games, it is still difficult to keep correct uniform distribution when picking more complicated random events, even while the actual random number generator has a good distribution. For example, consider picking a random point inside a disk, as is needed in certain games (usually some variation of bullet spread). Programmers without prior knowledge, specially amateur ones coding for a game mod can implement this random point generator in a way that there is [[http://mathworld.wolfram.com/DiskPointPicking.html a bias towards the center of the circle or towards its limits]].
** In DataStage it is possible to randomly generate the same numbers as in the course book for exercises, meaning it is completely predictable.
** Some languages, such as QBasic, allow the programmer to generate pseudo-random numbers using the system's internal clock as the seed, so the seed will be different every time a program is started.
** One particularly notable random number generator, known nowdays as RANDU, was noted as being, in the words of Donald Knuth, "truly horrible". It has since become a textbook example of a bad PRNG, due to many, many undesirable properties. [[note]] Among the lesser sins: only generating odd numbers if fed an odd seed value, and even numbers if fed an even seed value. Given that most programs feed the result in as the next seed to insure consistency across runs, this is not a trivial problem. [[/note]] (On the plus side, if your system is newer than the second half of the Reagan administration, and doesn't involve FORTRAN, it's highly unlikely you will suffer under this particular misguided PRNG.)
** Many versions of Linux have a very good PRNG as a system resource with a seed that depends on many hard-to-access and fast-changing internals of the system, making it difficult to guess what the next value will be, even if you have many recent values and normal programmatic access to the system.
* Averted with ''really'' cheap CD players. For some "random" is the playlist shuffled differently, and always that same order differently.
** Even more expensive ones will leave the user scratching their heads at the chances of two songs of the same artist back to back, or the fact that the system seems to throw up one artist more often that others despite the other 100 artists available.
*** This got so bad, so widespread, that Apple rewrote the "Shuffle" program on their newer iPods so that no two songs from the same artist are close to each other, if possible. Turns out people want ''high'' entropy from a shuffle, not ''random'' entropy.
** In the same vein, Pandora Online Radio. Sometimes it plays songs by the same artist (or in the case of Disney-based stations, merely the same album). And sometimes, on the Disney stations, it will play songs from things like... AvenueQ, between [[http://tvtropes.org/pmwiki/pmwiki.php/Disney/Frozen Do You Want to Build a Snowman]] and [[http://tvtropes.org/pmwiki/pmwiki.php/Disney/Mulan Reflection]]. Other times, the station will play songs that are wholly irrelevant to the station you started off on, based [[InsaneTrollLogic very loosely]] on songs you've liked on the station.
* A school of thought is that nothing is truly random, but rather, very chaotic. The forces that act on an object at any given point, even if static per se, can be graphed as a fractal (an infinitely complex shape). Since everything is only capable of a certain level precision, it's impossible to get the same exact result every time because you're trying to point a spot on something that's infinitely complex.
** It is only a school of thought, not reflecting reality. Actually, radioactive decay is truly random in the sense that nothing in the observable Universe has an effect on when an undisturbed particle will decay, and not just because of our sensors lacking enough complexity.
*** [[ScienceMarchesOn As far as we know]].
** This however is only a matter of which philosophical viewpoint you're taking, which cannot have an impact of our observation of "randomness". Using all our knowledge about the universe, we still could not predict any non random randomness (if it even existed), since we cannot observe closely enough (see Heisenberg) and we cannot compute all data from the universe without having some computing machine which is larger than the universe. So even if chance did not exist, we still will have to act and calculate as if it did. In other words - the existence non existence of randomness can never be proven since you can never assemble all required data, thus the question cannot be answered scientifically.
*** Basically: to prove randomness does not exist, you need to know every event that happened and the conditions that acted upon them.
*** It's also largely a question for the philosophers. Whether "true" randomness ultimately exists or not, the concept has too many ''practical'' applications to simply throw out.
* Some websites with a "Random Page" button keep sending you to the same article, and might even get stuck on it.
** One example is located directly above. Try clicking the 'random page' button a few times, and you'll start to notice that there's a few pages that are noticeably more 'random' than others. [[note]]What's actually happening is that the random page is chosen once a minute, to minimize server load.[[/note]]