Although in Real Life, donkeys are quite effective in pulling wagons, in media, the donkeys pulling the cart are often stubborn and unreliable, and don't want to do the heavy work. Of course, it doesn't have to involve carts.
Sometimes the ass is used as a symbol, not so much of stubbornness, as of sheer stupidity. It was probably this characterization that led to the modern usage of "ass" to mean "fool." On still other occasions the donkey is used to depict low status or servility, especially when contrasted with more favored beasts such as the horse or the hound. Finally, paradoxically, the mule has been used to symbolize sturdy, if stubborn, practicality, and a no-nonsense attitude towards the harsher realities of life.
Both these characterizations (ironically) come from the fact that donkeys and mules are more intelligent than horses and have a stronger sense of self-preservation. This makes them less obedient to humans, therefore we perceive them as stubborn, but consider: you can ride a horse to death, but a donkey will stop when it's exhausted. Which is smarter?
Note that strictly speaking, a donkey (or ass, of which a "jackass" is the male and a "jenny" the female) is a separate species; a mule is a (usually) sterile hybrid, a cross between a male donkey and a female horse, as opposed to a hinny, the offspring of a male horse and a female donkey.
Despite the name, this trope is not limited to mules.
- The eponymous donkey from the classic comic strip And Her Name Was Maud.
- In Gasoline Alley, junkmen Joel and Rufus ride around between disasters on a cart pulled (when she's in a good mood) by Becky, the mule.
- Patton: During the invasion of Sicily, a pair of mules pulling a wagon refuse to move, blocking a bridge and causing a column of American troops to be strafed. Patton shoots the mules and has them dumped over the side of the bridge, allowing the column to continue.
- In Der Schuh des Manitu, while the Greek talks about the cleverness of his donkey, the beast steps on the rails, refuses to move and gets killed by an express train.
- In Cahill, United States Marshal, John Wayne is left horseless and is forced to buy a mule from a farmer for lack of any alternative. There's a short clip of it bucking in protest when he mounts up, although it cooperates perfectly well in later scenes.
- The Ten Commandments has one of these during the leaving of Egypt.
Joshua: Four hundred years in bondage and today he won't move!
- The original Aesop had several fables centering on these.
- In one, an ass had to carry a load of salt, but accidentally fell into the river, the load dissolved, no more heavy weight. Next trip it threw itself into the river on purpose. The master got annoyed and had it carry a bunch of sponges on the third trip. It threw itself into the river again, but found that sponges get heavier when wet.
- In another, a drover is leading an ass that suddenly decides to take a path that leads over a cliff. The drover desperately tries to hold the beast back by its tail, but when he sees that the stubborn animal is about to drag him over himself, he lets go and lets the ass plunge to its death. The moral there is that there is no point killing yourself to save those who are determined to ruin themselves.
- In another, an ass is envious of the pampered position enjoyed by his master's lap-dog, who never has to do any heavy work. So he attempts to jump into his master's lap and lick his face. Hilarity Ensues.
- Bad Ass, Lancre was named for the fact that a donkey got stubborn there. The village was founded by the people riding in the wagon it was pulling. Now Lancrians have to explain it to everybody.
- In Jingo a donkey gets stuck up a minaret in Al Khali. Being the stubborn animals they are there is no chance it will back down. It can't turn around, and being right at the top it can't go forward. The locals are amazed at Vetinari when he disappears into the minaret and returns leading a docile donkey. Vetinari helpfully explained that the key is to find that part of the donkey that really wants to get down. He is holding a walking cane when speaking, suggesting mechanism.
- Animal Farm: Benjamin the donkey is never taken in for a moment by the pigs' false promises of Utopia, and refuses to undertake extra labor for it as some of the more idealistic animals do, but he also refuses to do anything to oppose the pigs.
- Invoked in Mercedes Lackey's The Fairy Godmother, the first of her Tales of the Five Hundred Kingdoms series. A stubborn prince who behaves like an ass finds himself transformed into one. His asinine behavior persists for some time until he loses some of his pride and subsequently reforms.
- One of Alan Dean Foster's Spellsinger novels has a talking hinny as a supporting character. (Mules have a horse mother and donkey father; hinnies are the other way around.) Yep, she's stubborn too.
- A Song of Ice and Fire has some rather intelligent, hermaphroditic "mules" wear scales and breathe fire. The key to Valyrian-brand dragon-riding seems rather geared towards making bloody sure the individual dragon both knows you and really, really likes you before you try asking it to do anything it might object to. Thwacking one with a stick when it decides it wants to snooze or because it's in the way is categorically not recommended. No more than walking up to one who doesn't know you, let alone accept you, and acting overly chummy is, even if you definitely have the right bloodline — more than one Targaryen and Valeryon princeling found this out over the years. Possitive reinforcement, yay!
- Actual mules, donkeys and hill ponies/horses (moor-, Shetland- or Icelandic analogues) also show up. Although not widely deemed as impressive as a warhorse, let alone a dragon, they are essential if you want to get around the wilder parts of the Seven Kingdoms in anything like decent time. For climbing up to the Eyrie or trekking around and beyond the Wall, you need reliable, hardy stubborness that's both willing to balk at mutually suicidal directions and can just keep ticking along on even dodgy forage. As Stannis finds out when he tries ploughing Southern-bred slabs of hay-guzzling muscle through autumn snow. The poor war- and draught-horses weren't bred or trained for that.
- The season 12 opener of The Amazing Race had a challenge which involved transporting peat using a donkey, most seemed compliant enough but the donkeys used by Ari & Staella and Nathan & Jennifer proved to be premiere examples of this trope, resulting in both teams placing in the bottom rung.
- In season 1 of the Australian version, Richard and Joey got a stubborn goat that didn't want to go where they had to take it, resulting in them being eliminated.
- On Dirty Jobs, part of Mike Rowe's visit to a California camel ranch involves rectally taking the temperatures of several camels. When he jokingly asks if they're going to do the same for the ranch's donkeys, his host hastens to make it clear that handling the donkeys is a much different undertaking than handling camels: "You don't do anything to a donkey unless you ask first."
- The Bible: The prophet Balaam being hired out to curse the Israelites struggles with a stubborn mule, until the mule is granted the ability to speak and reveals that she was trying to protect her master from a vengeful angel.
- In Red Dead Redemption, while traveling through Mexico, you'll occasionally encounter a peasant leading his donkey down the road. The peasant will loudly and repeatedly curse the beast in Spanish. You yourself can ride donkeys, but they won't jump, they can't run as fast as a horse, and if you try putting a hogtied person on one, it won't work.
- Parodied in a Family Guy cutaway, where a mule plays the Six Degrees of Kevin Bacon game, and refuses to admit that he was in Footloose.
- Averted in Disney's The Small One (directed by Don Bluth) in which the eponymous ass is gentle, patient, and quite amazingly self-sacrificing.
- My Little Pony: Friendship Is Magic:
- Applejack is actually less patient then an actual mule.
- Cranky Doodle Donkey is old, set in his ways, and very, very unwilling to deal with Pinkie Pie. After a while, you start to empathize with him.
- There's an actual (nameless) mule who shows up when one of the protagonists says how somepony else is "as stubborn as a mule", prompting them to quickly add "No offense!" Humorously, the actual mule never does take any offense, implying that he's actually more agreeable than the ponies.
- Donkey in Shrek is implied to be one of the stubborn donkeys from Aesop's fables listed above, as the first time we see him he is about to be sold into bondage by his owner, promising to never be stubborn again. After this, Donkey's stubbornness is mostly an Informed Flaw, as he's generally pretty agreeable and willing to do some dangerous feats. He is stubborn in one regard, though - making friends with Shrek.
- In the American West, J. Golden Kimbell, a Mormon leader, was infamously known as The Swearing Apostle. "As a young man he had worked as a mule driver. And as everyone knows, mules are twice as stubborn as any other creature on earth. And these were Church-owned mules! Church-owned mules are ten times as stubborn as ordinary mules. You had to blister them with the coarsest oaths known to man for over two hours just to get them to move ten feet. I was the best mule driver in camp, and my language showed it."
- This is the reason they were used to carry equipment in mountainous terrain, horses were just too damned obedient to choose a safe path. They're also generally tougher than horses, making them a good choice for the military for getting to places where vehicles can't go (European mountain-based militaries have done so for centuries, and as they were abandoning them the USMC started using mules in Afghanistan).
- The American Democratic Party has a donkey for a symbol. This is sometimes said to originate—like so many American political terms—with an insult: namely, calling Democrats "jackasses" because they supported Andrew Jackson. However, the link between the Dems and the donkey was cemented by political cartoonist Thomas Nast in the late 19th century, who drew the Democrats as a donkey stubbornly but futilely kicking the Republican elephant (itself chosen to represent the GOP's domination over Gilded Age politics). Democrats continue to emphasize the use of the donkey as a representation of stubbornness...although today, the reason for the donkey's stubbornness (intelligence) is also emphasized.