The word "fool". Try it out. When someone disappoints you or does something stupid, throw the word out. C'mon, give it some gusto. You fool! You...(deep breath, now) FOOL! Got the hang of it yet? No? It just sounds silly in real life? Well, get used to it, because fiction? Fiction loves this word. It's the ultimate insult. Every villain uses it, every hero with a hasty friend uses it...Hell, if we were to list every example we could find, it'd just overflow the page. It's so common. Only really prominent examples should be listed.
Interestingly, we may have the Hays Office's old Production Code to thank for this. In the olden days, most mainstream works couldn't use profanity. How to show that your villain is one bad dude when his language is carefully scrubbed with bleach? Well, according to The Bible, whoever says "You fool!" is in danger of the Lake of Fire. (Matthew 5:22) Thus, having your villain call his rival a fool allowed the audience to know that this guy was bad news without resorting to using any verboten words.
"FOOL! Did you really think you could harm me!?", as said by the Bad.
"You fool! You've doomed us all!", as said by the Bad's advisors to him when he activates the superweapon.
"You really think this is about money? Don't be a fool," in cases of motive misidentification.
"Foolish mortal!" in case the one who said it is a greater being than human.
"Foolish Fool!" for when the person and their actions must be lauded.
Dragon Ball GT's Super Android 17 says this when Goku tries to kill him with a Kamehameha, thinking his absorption ability will cover it. Trouble is, Goku just put a gaping hole in his midsection, so he's in no state to absorb anything. In video game adaptations this becomes one of (both normal and Super) 17's go-to phrases when countering attacks.
Mortal Kombat: Shang Tsung says this a lot whenever someone fails him. Also said it when Liu Kang punched him in the face. Ironically it made Shang Tsung look like the fool not Liu, since the whole point of Mortal Kombat revolves around hitting your opponents.
In "Harry Potter and the Goblet of Fire", this is Professor McGonagall's reaction to Fudge refusing to believe Voldemort has returned: "You fool! Cedric Diggory! Mr Crouch! These deaths were not the random work of a lunatic!"
"Robots have learning capacity, you . . . you fool—" And Bogert knew that she had really lost her temper.
At the climax of the second Warrior Cats series, Hawkfrost informs Brambleclaw that he is a fool... and stupid.
"Fool" shows up a lot in Animorphs. It's treated as the ultimate slap in the face when Alloran tells off Seerow for giving the Yeerks technology. Visser Three likes to yell "Fool!" and its variants at his underlings a lot, also. Usually about three seconds before offing the sucker.
In the Dragonlance novel Dragons of Spring Dawning, Laurana repeatedly calls herself a fool after realizing that she has allowed her Arch-Enemy Kitiara to trick her into getting herself and her friends captured.
In Making Money, Mr. Bent is having a crisis of conscience and the voice criticizing him culminates in "you fool. You fool." It's pretty much the last thing he wants to hear, because he is literally a clown (he only tried working as one once, but it's apparently In the Blood) and has made every effort to stifle that part of himself. It shocks him into making a mistake and running into the gold vault.
This classic Hollywood Squares clip, where the Epic Fail of the contestants led to the panel calling them fools as a Running Gag. (To elaborate, Gilbert Gottfried was the last square available and a contestant would only have to answer his question correctly to win. They couldn't, failing seven questions in a row. The first time, Gilbert shouted "You fool!" mimicking Penn Jillette's Chewing the Scenery; and soon the entire panel was joining in.)
Another one in Next Generation: The Enterprise encounters a Klingon vessel whose crew had been placed in suspended animation almost a century earlier and doesn't know about the truce with the Federation. Worf and Klingon Emissary K'Ehleyr are placed in (temporary) command of the Enterprise to deceive the crew into thinking the Klingon Empire was victorious.
Worf: You fool! Did it not occur to you that the war would be over by now?
Star Trek: The Original Series episode Day of the Dove. Kirk has just explained to the Klingon captain Kang that the Enterprise is under the control of a creature that feeds on hate and wants the Klingons and humans to fight for its entertainment for the rest of eternity. Kang decides to fight Kirk anyway, at which point his wife Mara exclaims "You fool!".
Later, Kang himself admits "Only a fool fights in a burning house."
Around the start of the 8th season of Scrubs, one of JD's fantasies, didn't end well for Dr. Cox. When he snapped out of it and looked at his mentor, he commented, "You proud fool!"
Lord Dread has done this at least once in Captain Power and the Soldiers of the Future, most notably when Hawk's diversion prevented the Bio-Dread Soaron from destroying Power's ship during the run on the Icarus Control center.
In an episode of The Drew Carey Show, Kate caught Drew cheating on her with an old girlfriend. Later in the episode, Drew drops in on Oswald and Lewis and tells them that Kate's pissed and looking for him.
Lewis: You fool! You've killed us all by coming here!!!
In The Protomen, Protoman is fond of calling humans fools. Cause they are.
In Act II, Dr. Wily calls Light a fool for thinking humanity will resist him.
In the musical segment of Cheech And Chong's "Earache My Eye", the singer (Glam Rock parody AliceBowie) shouts maniacally at the end of his song, "Watch me burn, ha ha ... YOU FOOLS!"
Stand Up Comedy
In a stand up act done by Bill Cosby, he recounts how he and his friend "Old Weird Harold" went to see a horror movie marathon and had to walk home after dark. They were frightened by the sudden appearance of a wino and beat him up before running away. Bill imagines the wino making an accident report:
Cosby: Now I'm sure, while filling out the accident report on this man, that the doctor said, "What happened?"
"I don't know. It's just, four feet ran right up my chest, danced on my head for a half-hour and then ran straight down my back, doctor."
"Well did they say anything?"
"Yes, they said, 'WAAAAAAAAAAHHHHHHHHHHH!'"
"Did you see them at all?"
"Yes, there was a little kid riding on top of a tall skinny one and he was beating him with a stick saying, 'Faster, faster, you fool, you fool!'"
In Eternal Darkness, Pious calls Ellia a fool twice, first for being so close to Mantorok and then for not following his advice to run away.
Garland from Final Fantasy calls out the Light Warriors as impertinet fools right before the knockdown.
LIGHT WARRIORS?? You impertinent fools. I, Garland, will knock you all down!
In Diablo 2, Tyrael uses this when Marius takes Baal's soulstone. 'You... FOOL! You have just ensured the doom of this world!'
Kerrigan in Starcraft II will repeat this phrase or a slight variant of it many, many times during the campaign.
In Kid Niki Radical Ninja, the fifth boss, Mad Monk, uses this phrase as his primary weapon. He can say it softly and drawn out ("Fooooooooollll..."), extending across the top of the screen to drop Os on you; he can shout it out as a large kanji with which to crush you; or he can scream, "GET HIM, YOU FOOLS!" to summon some mooks to take you out, or at least keep you distracted enough to fall for one of the first two.
Lord Victor Nefarius, aka the Black Dragon Nefarian from World of Warcraft gives us this Genre Savvy line when he berates his incompetent minions:
Subverted, though, by the time you face Nefarian himself, he has forgotten his own advice for your convenience.
It makes sense, though - when you're watching a fight, figuring out who the biggest problem is easy. When you're the one getting smacked upside the head by a guy wearing plate armor, but the guy in the dress is doing nothing visibly harmful to you, which would you reasonably go after? He makes up for it somewhat, though; instead of trying to kill the medics first, he screws with them in various ways (Priest heals can suddenly start to cause damage over time to the targets, druids can be forced into cat form, etc.).
Used by the Spy in Team Fortress 2 as one of his responses, upon dominating an enemy Spy. Given the air of sophistication and competence the Spy tries to maintain, he treats this this as a grievous insult.
In a Mages' Guild quest in Oblivion, a count's steward informs you that the count wishes to meet you outside of town at 2 am. The steward shows up there with a couple of necromancers, tells you that he tricked you, and tries to kill you. The count himself arrives and helps save you. Afterward, he angrily says: "You impossible fool. What possessed you to think I would suggest a meeting here, of all places?"
In Skyrim, a Dunmer trapped in a Giant Spider's web offers you a MacGuffin for cutting him loose. When he's freed, he says, "You fool. Why should I share the treasure with anyone?" before running further into the dungeon (most likely to get to the door the MacGuffin is supposed to unlock). If the player doesn't get him, the draugr or the booby traps will.
Red vs. Blue: O'Malley, in his quest to over-do every single supervillain trait he could, delivered this line:
O'Malley: "You foolish fools will never defeat me! You are far too busy being foolish!"
Because the idiocy of his AI teammates, (At least in their inability to throw a flash grenade more than a foot into the room) this has become Noah Antwiler's phrase of choice during his Let's Play of ''SWAT 4''. There's even a shirt.
Lampshaded once when Spoony does it to himself and instead says "Erm, me fool!".
Also shows up in live-action shows for kids as well. After Hawk buys Captain Power and the Soldiers of the Future time to get to Icarus Control by going after Soaron, Lord Dread, overseeing the whole thing, utters "Soaron, you fool!"
In the Beast Wars episode "Gorilla Warfare", Optimus Primal yanks a viral mine off of his chest while inside the Predacon base, prompting Megatron to yell at him "You fool! You'll destroy us all!".
Most Disney villains have called either their enemy or their minions fool at least once, likely for similar reasons to the founding uses: Disney, having earned their reputation by providing family-friendly animation in the first place, court G and at most PG ratings instead of avoiding them. So instead of profane insults you get a lot of "you fool!" and "you idiot!"
101 Dalmatians (1996):
Cruella de Vil: You're a fool, Anita! I have no use for fools.
One of Futurama's TALES! OF! INTEREST! has former Vice President and protector of the space-time continuum Al Gore shouting "You fool! You foolish fool!" at Fry, after he's just caused a time paradox that will destroy the universe.
Samhain: You didn't actually think you could keep Samhain, the Spirit of Halloween, locked up forever, did you, Ghostbusters? Peter: Well, yeah, actually we did. Samhain: Then you are fools! And fools deserve a swift demise!
Homer Simpson on April Fools day. "You couldn't fool me on the foolingest day of your life if you had an electrified fooling machine."
Similarly, the (for now) defunct Star Trek: The Experience attraction in Las Vegas had one of these on each of its two shows. The Klingon Encounter featured Korath angrily spitting at Riker, "Fools! You will regret defying me!" The Borg Invasion show featured the Borg Queen's admonishment when her threat of employing a self-destruct sequence is questioned, "You're a fool, Janeway! There will always be more drones."
This was the standard insult for the first few years of BIONICLE, but has lately been replaced by "idiot" and "imbecile".
"Climb you fool! Climb!" was shouted in futility at the B-25 bomber that mistakingly crashed into the Empire State Building in 1945.