You can use asteroid fields to help pare down unfavorable odds, by leading the enemy through them. The AI is, in general, really dumb about avoiding those floating bits of astrogeography, and will gladly suicide on them.
Especially in the earlier games, the player's wingmen were a little too enthusiastic about shooting down the enemy; i.e. : they would cheerfully ignore that the player was in the way... At times, it seemed like when your Wingman was Maniac, he did did it on purpose.
The spinoff Privateer 2 had completely incompetent enemy AI. Spoony, in his review, parked his ship next to an enemy and waited to see how long his unmoving, unacting ship would take to be killed. After half an hour in which the pirate once managed to wear down the shields, he gave up entirely.
Sims tend to get stuck at a doorway, unable to decide who goes through first for several minutes. In the original game, this bug used to strand entire groups of Sims at the top of staircases. Sims have been known to starve to death because they couldn't take turns.
Ironically, Sims actually do have good pathfinding when it comes to things less complicated than, urm... doorways. Try building a maze, for example, and the pizza boy will walk right through.
It should be noted, though, that Sims 1 Sims will almost always take the path with less doors to get to their destination, even if the destination is on the other side of a door right next to them.
Sims are, however, known for such suicidal stunts as, when both hungry and tired, waking up to go eat, then passing out from exhaustion, waking up because they're too hungry to sleep, then passing out because they're too exhausted to eat, in a vicious cycle that generally ends in sim ghosts.
However, that's not the AI's fault, but the oversimplified needs system.
Sims will also drop a baby on the floor in front of the refrigerator, then complain that they can't get to the refrigerator to get the baby a bottle...
And let's not forget the sims who whine about being exhausted, then decide there's no better time for a swim.
Try giving your sims more than one kitchen (especially on different floors) and watch as they dart between the two in order to prepare a single dish. Alternatively, make the only food preparation area available an outside barbecue, and occasionally the AI will have a sim go for a midnight snack - so, having no other option, they will go have a cookout in the middle of the night.
Sims have sometimes been known to go to sleep, and wake up to yell at the player that they're sleep deprived.
Happily, as of Sims 3, the AI has improved immensely, and Sims are entirely capable of handling the basics of living.
Well, to some extent. Give a home with two adults and a child only one bed, and anyone left without a bed will complain at those using them. There is no check for the appropriateness of doing so, so the husband may find his wife and daughter sleeping in the only double bed, and order the WIFE out of it.
Oh, and Sims 3 sims will happily sit and eat their dinner on the toilet if there isn't a spare chair. Hey, if you can sit on it, it's fair game, right?
The Sims Medieval lampshades this in its opening cinematic: "People are dumb." Medieval Sims seem to have some of the same stupid traits as their descendants when it comes to pathfinding (they think a Sim is "in the way" when they're trying to get into the Throne Room, even though the Throne Room's doors are twice the size of a Sim) but at least they never start fires when trying to cook.
Hey, you know that theatrical voice in the opening Cinematic? It's Patrick Stewart. That's awesome!
Sims are pretty dumb on the macro level as well, as anyone who's ever played SimCity 4 can attest. The stupidest is definitely pathfinding, where for various reasons Sims always take routes in a manner that tends to create absurd traffic jams, particularly at the city limits.
The AI in Gemfire is just plain bad, sometimes giving up the chance to seize the player base and not attacking with its 5th unit at all. Even worse: they don't seem to be able to grasp the fact that their base is under siege, AND they will set a unit on their base and surround it with fences, thus being an easy target for Archers. Not to mention the computers will try to form an alliance with you right before they're about to die at your hands...only to cut the alliance when it's just you and whoever you're allied with.
The animals and staff in Zoo Tycoon can be unbelievably stupid sometimes. For example, animals will be unable to find food when there are three piles of food right next to them, or zookeepers will not be able to get to poo and clean it up for no reason at all.
RollerCoaster Tycoon was particularly bad with this. First of all, unless you destroy the paths at strategic places, every Guest in the game will go wandering off miles beyond any sign of civilization and then complain that they are "lost". Interestingly, they cannot walk ten feet on an unpaved surface, meaning that if you create a path with two dead ends, the Guests will just walk back and forth until the end of time. The Handymen Staff were pretty bad too. Though all you wanted them to do generally was sweep up puke, if you left the command on for them to mow lawns, they will wander off spending hours mowing the endless acres of your theme park while your Guests swim in rivers of their own vomit. And mowing lawns is pointless anyway, because there's a glitch in the game that solves it with ease. If you just touch a piece of land with the landscaping tool, even without actually doing anything, the weeds will disappear. Luckily the sequel just turned the Mow Lawns command off.
The "No Entry" signs in the expansions solved the problem of guests running off in the first game, but still doesn't keep them from getting lost. Guests will claim to be lost while pacing in front of the exit.
Mechanics also had this problem. If the paths aren't laid correctly, your rides might spend a while not getting fixed because your mechanic spends his time pacing around some other area in the park trying to get to the ride.
Try building a central square with shops all around and watch the visitors aimlessly mill about...
The various boat rides on RCT 2 have a habit of making all the boats cluster around the docking station, blocking each other out of it, with none of them able to enter.
And talking of Chris Sawyer... the AI in Transport Tycoon was legendarily incompetent at the art of building railroads, frequently levelling entire mountain ranges (and suffering no ill effects), and often spiralling stations several times over while trying to get the ends of a line to meet up. Reportedly, this was due to a compromise between processing time and AI lookahead. Having the AI build from both ends at once, effectively meaning both are aiming for an unpredictably moving target, probably didn't help either.
Fixed in Open TTD (fan made sequel)
Without going into too much detail, let's just say that in Creatures 2, the Norns that come with the game are retards. Thanks to a problem in their digital genetics, this gets worse after their first real-time hour of life (the so-called "One Hour Stupidity Syndrome", based from the fact that the reward values in the Norn's artificial brain are so screwed up that they'll most likely to be eventually sitting around deliriously happy while starving to death in the middle of a forest fire). A player may find that in order to make any progress in the game whatsoever (with getting pickups and exploring and the like) they'll have to micromanage one Norn and spent a distressingly large amount of time luring it into the water so as to pick it up and make it go where the player wants it to. There's a play style called the "Wolfling Run" where you hatch a bunch of Norns and leave them to their own devices - since the default Norns are outsmarted by buttons and fail to connect hunger with the need to eat, this is an exercise in genocide. The modified Norn "Socrates", designed specifically to remember none of its experience of reward or punishment for its actions, essentially ruled by random instinct, ended up prospering much better than it's default cousins, granting insight that allowed the game to be fixed.
Game Mods fixed this in C2, but even in the later games, Creatures still tend to gravitate toward "charming" over "clever." Most all the creatures games feature "wallbonking"—the continued attempts of a Creature to walk through a wall, despite their initial failure to pass through it. They also do things like attempt to eat machinery or ignore food because there's something shiny right beyond it.
Space Colony has the problem that if a characters shift is over they will ignore the job responsibility, even if that is defending the base from aliens or keeping the air supply running.
For some reason, the title Pikmin sure do love to drown themselves when you try to cross a bridge with them.
It's noted that without before Olimar came to the planet, the Pikmin were basically a sentient food supply for the herbivorous creatures inhabiting the planet, and that Olimar's efforts in organizing them have helped them to survive once Olimar is gone. In other words, the game justifies the stupidity, as the Pikmin were literally a walking food supply before Olimar came around.
Star Wars: Rogue Squadron for the N64 does this big-time. Your allies are completely, absolutely useless. All they do is fly around, sometimes in circles, leaving the player to do the work of an entire squadron himself. Of course, the enemy is not much better. TIE Bombers especially suffer from this: they always fly in a straight line and never even attempt evasive maneuvers, making it ridiculously easy to shoot them down. On the other hand, the TIE Interceptors in Moff Seerdon's Revenge, who shoot at angles their cannons can't hit any other time, are cheating bastards.
It doesn't get any better in the sequel, Rogue Leader (suggested alternative: Rogue Suggester), wherein any command given to your squad is usually interpreted by them as "Fly very slowly near the turbolasers". They also delight in using lasers against enemies vulnerable only to special player-only weapons, or shooting up the unbreakable walls between them and their target instead of flying around to the other wide-open side.
Perhaps as a result of this, it's possible in the second and third games to order your allies to retreat.
In Rogue Leader, you also have Darth Bob the Suicidal TIE Pilot. You could be minding your own business and then suddenly BOOM Collision with a TIE fighter out of the blue, and you never saw it coming.
The ancient Star Fleet Battles simulator BEGIN 2 has surprisingly good AI. Except for the Romulans. These guys will set off their self-destructs occasionally for no obvious reason, often destroying other ships (friendly and enemy) nearby. As the Romulans can also cloak this makes fighting them like going for a walk in a minefield.
The AI controlled ships in Star Trek Klingon Academy suffered from a total lack of spatial awareness. This meant that if you were battling the enemy near an asteroid field, all you had to do was fly into the middle of the field and sit back as the enemy ship(s) plowed into every asteroid nearby and most likely ended up destroying themselves.
The original idea was that you'd be limited in the amount of micromanagement you could do per turn ? you basically played as the ruler of an empire with a horrible bureaucracy. That turned out not to be much fun.
The "Auto-Build" option on colonies, while useful, often results in your 1 population, mineral poor colony attempting to build the most expensive building (the Star Fortress), which take 50+ turns, before industrial buildings that will help other things build faster.
AI ships in space combat also love to uselessly fire energy weapons at planets with impenetrable shields.
AI ship design aims for a Jack Of All Trades design that has a little bit of everything for every possible use, resulting in ships that often are unable to press the advantage against a weakened foe before they can recharge their shields in the next turn.
The ants in Bugdom will throw their spears, then run to fetch them. If you can get them to throw a spear through something, they will just sit there, running against a log drinking straw. In later levels, Fake Difficulty comes into play as the ants gain the ability to return from the dead as invulnerable ghosts, still thirsting for your blood, as a way of counteracting this kind of thing.
The propensity of AI-controlled ships in the FreeSpace series to crash into other ships that are in the way has become a running gag among fans. Other idiotic things the AI loves to do include continuing straight on an attack run even though the player is behind them and firing, flying directly into beam cannons, firing beam cannons at enemy capital ships even if friendly units are in the way and will be annihilated, and firing torpedoes from the longest possible range, making them easy to intercept and shoot down before impact.
In Animal Crossing some villagers are less than bright with trading one item for another.
Your mech wingmates in Steel Battalion can barely navigate the map, though, when they manage to keep up with you, they can be useful cannon fodder.
In F/A-18 Hornet, your wingman is pretty much useless, and the planes you have to escort aren't much smarter.
This is the biggest complain people have had about From Dust, where the villagers' pathfinding AI can be a pain in the ass to manage. Most of the time, even the slightest obstacle will cause them to either take a massive detour, or start begging you for help while they stand still in bewilderment. Walking straight into streams of lava doesn't help either.
Aerobiz: The AI would continue to purchase small counts of outdated, inefficient airliners even after newer, cheaper and more efficient planes are made available. would regularly place the largest, most inefficient airliners in its fleet on low density routes and then leave them there despite losing big bucks and its competition (you) opening the same route with a small, high efficiency airliner and turning a profit.
Elite: it was less stupidity of the pilot and more stupidity of the space traffic controller/random event engine, but passenger shuttles would periodically launch from space stations regardless of surrounding traffic. Even if that traffic was you, less than a second away from docking (and yes, incoming and outgoing traffic used the same lane). While the collision wouldn't destroy your ship unless it was already damaged, it would destroy the shuttle—and hit you with a massive bounty for criminal activity, to be collected the instant you left the station.
The AI allies in Tom Clancy's HAWX are incredibly reluctant to actually use their missiles on targets you've sent them after, and they refuse to use guns if they still have access to said missiles, which overall cripples them horribly. About the only time they approach usefulness is in missions where, for plot purposes, everyone on your side is restricted to guns-only, which is the point where they shred everything.
Dwarf Fortress. Strangely enough, part of the game's charm has to do with the fact that your dwarfs are utter idiots. However, they make some choices that lead to... odd happenings. For example, if an executioner doesn't have a weapon to kill a prisoner with, they don't let that bother them, and kill the prisoner anyway. By biting them to death.
Similarly, hunters who run out of bolts will gladly bludgeon the animals to death. And if they somehow lose the crossbow, they will gladly (and oddly successfully) wrestle muskoxen and elephants to the ground.
Then, there's sieges. The most common kind, goblin sieges, may leave players overconfident because the average goblin siege charges right into your traps and lets themselves get slaughtered. Eventually you face human sieges where they, well, do a proper siege. They sit right outside of your crossbow range and wait for your dwarves to run out of food and water and/or tantrum and start slaughtering each other. Any attempt to foray is met with a withering storm of bolts and arrows which, because DF averts Annoying Arrows, is very deadly indeed.
Actually, in the same way Team Fortress 2 is sometimes described as a "hat simulator with gameplay on the side", Dwarf Fortress can probably be reasonably described as a "stupidity simulator with gameplay on the side".
An odd combination of stupidities leads to hilarious results: "Ignis promptly starts to spar and get a punctured lung. Instead of being a good wounded dwarf and staying in bed, he promptly walks around the fortress falling unconscious, refusing any medical care whatsoever. This I could tolerate because it meant the idiot would be dead soon and no one would care. After traveling to my royal dining hall in just under a year, he proceeds to grab a plump helmet stew from my nearby food stockpile. He then promptly falls unconscious again and drops his food in the hallway. The stew proceeds to rot and create a gigantic amount of miasma and there is nothing my dwarves can do about it since the stew is owned by Ignis. After waking up half a season later, Ignis, seeing his stew has rotted, proceeds to the stockpile once again to grab some cat biscuits. You can see where I am going with this."
When there's a siege or other such hazard present on the surface, you can order your dwarves to "stay underground" to keep them safe. The way the dwarf AI does this is to continually check "am I aboveground?" and if so, cancel whatever task they were doing. The jobless dwarf will then pick a new task from the list of available tasks... which is often the very task they just cancelled. The result is known as the "entrance dance", where a huge crowd of dwarfs winds up clustered around the entrance constantly jumping back and forth through it and announcing cancelled jobs. Most players will have to design their fortress with an outdoor courtyard of some sort to keep these idiots safe.
A variation is when you have a dwarf or two outside doing a job when an enemy of some sort shows up near the door, but without being able to reach your dwarves, i.e. because you have a walled-in courtyard. Dwarves are dumb enough to run away from any enemy they can see, even if they can't reach them, so they will cancel their job and run away, most likely into the corner of your keep rather than back inside. The job cancellation causes another dwarf to pick up the job, which will take them outside, where they see something scary and run away, cancelling their job in the process. Repeat until your entire fortress is panicking in the far corner of your completely protected, walled-in outdoor keep.
Siege engines such as ballistae are operated by civilian crews, not military dwarves. That means that if you order your civilians to hide inside while your military fends off a siege, and the ballistae are outdoors, they'll abandon their posts. They'll also abandon their posts and flee if they _see_ a hostile enemy. Doesn't matter if the enemy is across a moat and through an impenetrable fortified wall, and that they're currently manning a contraption that an slaughter them all in a single shot...
When dwarfs are digging trenches or building walls they have a universal preference for which side of the wall or trench they stand on while doing their work. For example, they prefer standing on the west side of the tile if that space is available. So one must be careful about how you set up your construction orders or the dwarfs can wall themselves up and eventually die of starvation or thirst.
Nobles have an unfortunate tendency to mandate the production of items your dwarves have no hope of producing, e.g. windows in a location without sand. Their stupidity frequently leads to beatings and imprisonment for skilled dwarves who lack the raw materials to work with.
In previous versions a (now resolved) bug could result in mayors ordering themselves beaten for failing to satisfy their own mandates.
In an example of If You Die I Call Your Stuff taken to the extreme, the infamous BoatmurderedLet's Play features dwarves rushing to loot the possessions of their fallen comrades in the middle of an elephant invasion and get trampled to death, only for additional dwarves to rush for their loot...
Dwarves have been known to steal the clothes from a comrade who burned to death. While said clothes are still on fire. I lost a whole fortress to that one.
From an older version's release notes: "stopped people from giving quests to kill themselves."
Prior to the Adventure Mode overhaul, you could receive quests to slaughter demons who had risen from the depths of the Earth and taken control of a civilization. Your quest-giver's civilization, usually. Doing the deed would make said civilization your enemy, including the one who had given you the quest in the first place. One better, the involvement of your companions or the demon attacking other peasants may well start a "loyalty cascade" where everyone starts killing everyone for killing anyone.
Since the ability to target specific body parts was implemented there have been many cases of units fruitlessly punching, kicking, or biting their enemy instead of using their weapons because they randomly get some moves (involving a random kind of attack and body part) very high chances of connecting without factoring in if it could even do any damage.
Similarly, wrestlers have a habit of repeatedly grappling a body part, then letting go to grab another part, instead of following up those grapples with any actually damaging moves. Particularly annoying when you know how devastating a wrestler who actually knows what they're doing can be in Adventurer mode.
A dwarf got a small cut on his arm, which needed to be cleaned and bandaged by a medical dwarf. A second dwarf with no medical experience was drafted to take care of it. The newly minted doctor looked at the small cut, diagnosed the patient as having rotten lungs, and performed surgery to remove both lungs. The patient did not survive the operation. (Source)
It may count as subversion as it is an implemented, deliberate stupidity.
Dwarf tries to "attend meeting" with siege operator, stands on ballista set to "fire at will," gets injured
Goblin leaders have been known to turn up riding on tamed giant toads, which is mildly unnerving... until the toad hops into a murky pool and the goblin drowns.
When crossing a river, the AI only considers how deep the water is, and ignores how fast the water is flowing. Due to a quirk in how liquid flow is simulated, water is only leg or ankle deep at the lip of a waterfall. Thus, everyone tries crossing there, and gets swept over by the current.
Mothers carry their babies with them everywhere... even into battle.
If an invading army spots one of your pet cats wandering around outside, they will make sure that cat is killed, even if doing so requires that they ignore your fortress as the entire army spends days on end chasing the single cat around.
It's very possible for a brewer to completely ignore the fact that the entire fort is dehydrating to death because the caravan that you bought all the cloth and leather off just left. It's also possible for said brewer to stop brewing to throw a tantrum because he's thirsty.
X-Wing had one mission where you were in an A-Wing and charged with immobilizing a frigate. Since your A-Wing doesn't have ion cannons, you had a group of Y-Wings with you. Not only were these Y-Wings piloted by complete schmucks in the area of dogfighting— they weren't even smart enough to realize that their ion cannons depleted the frigate's shields at a slower rate than their blasters. Since the frigate is CONSTRUCTED FOR STARFIGHTER DEFENSE, this mission usually involved telling your "wingmen" to stand off outside 6 klicks while you soloed and 1) Defeated the entire 36 fighter TIE wing the frigate carried, and 2) Reduced the frigate's shields to zero by flying in and blasting like hell and then bolting out of turbolaser range again and again. This was made even stupider (and more frustrating) by the knowledge that the Y-Wings carried about 30 proton torpedoes— if they'd used THOSE the frigate's shields would have been reduced by 95%. Grrr!