Oh great, Alice is making one of her "suggestions" again, and Bob is just getting ready to deploy the mandatory response when Alice suddenly begins to make sense. "Hang on!" Bob says. "That's a brilliant idea... why didn't I think of that?"
This is when a character suggests something to another character that they wish they'd thought up, or are even surprised they didn't think up first. Despite the opening this doesn't have to be a previously dim or spacey character surprising a smart one (though that version may overlap with Dumbass Has a Point); simply suggesting something that in hindsight seems obvious can catch any character off guard. Compare Glad I Thought of It, where the character not only wishes they'd come up with the idea but tries to pretend they did come up with the idea.
- In My Hero Academia: Two Heroes, Kirishima gets smacked into a wall during a fight, and he can't get out because the jagged edges caused by his quirk keep him wedged into the hole.
- Oscar Wilde:
Oscar Wilde: I wish I'd said that.
James Abbott McNeill Whistler: You will, Oscar, you will.
- Milton Berle, who was memetically known for stealing other people's jokes, would often use this on himself (and obviously, the bit itself was stolen from Whistler, above).
Berle: (quoting back a punchline that was just said) I wish I'd said that.
Other person: You will!
- In an early Thunderbolts issue, the superhero Citizen V (actually a disguised Captain America supervillain, Baron Zemo) confronts Fantastic Four villain the Mad Thinker, who explains his master plan. "V" responds that "it's a good plan. I see no reason why it wouldn't work. Except, of course, for me."
- Ultimate Marvel
- Ultimate Spider-Man: Kong wants to fight Crusher Hogan and get five hundred dollars, but the manager did not allow him: he's a minor. Peter made a mask for himself and simply jumped into the arena without asking. Kong was there, and thought that it's what he should had done as well.
- The Ultimates: Thor wants to know which is Stark's motivation for being Iron Man. Perhaps being in a super team allows for some big corporate tax dodge? Unfortunately, no.
- Ultimate X-Men: Wolverine and Sabertooth have kept "killing" each other for years, but they always survive because of their healing factors. So Sabertooth had an idea: drown him. What use can a healing factor be if Logan's brain is severely damaged?
- The Reason why the Second Meta-Liberation War is going to be Weird: Izuku suggests to Re-Destro that he could use a sword coated in excess stress energy, leading to this response:
Re-Destro: Notebook, my boy. When it comes to creating support equipment, one has to consider not just "how good something is" but also whether it's economically feasible and whether the designs can work, as simplicity is important. Making things more complicated makes them more likely to be damaged in combat or malfunction.
Midoriya: [looks down]
Re-Destro: [dryly] However, this is a sword. And I'm the richest person in the country. [to engineers] SO WHY THE HELL DON'T I HAVE A GIANT KATANA TO CUT MY ENEMIES DOWN WITH?!
- In Sword Art Online Abridged, when Asuna asks Kayaba why he revealed himself for locking the players in Aincraid rather than blame a fake terrorist group, he admits He was too sleep deprived and paranoid to consider it and really wished he thought of her suggestion before hand.
- A Bug's Life: Used as a sarcastic response to Flik's suggestion that the colony should find bigger bugs to fight off the grasshoppers.
Queen: Now, why didn't I think of that? Oh! Because it's suicide!
- Peter Pan: Captain Hook does this when he's emotionally manipulating Tinker Bell into revealing the location of Peter's hideout, with the promise that he will help her get rid of Wendy.
Hook: What's that, my dear? You could show us the way? Why, I never thought of that. (aside) Take this down, Smee.
- The Sponge Bob Movie Sponge Out Of Water: When our heroes venture to the surface world and see Burger Beard selling Krabby Patties with the formula he stole:
- In Harry Potter and the Half-Blood Prince, both Harry and Hermione are annoyed that they can't go to Slughorn's party with their respective love interests, who are in other relationships. Hermione tips off that she's slummed to asking the infatuated Cormac McLaggen; Harry points out it would've made more sense for he and Hermione to just go together instead, prompting the trope response from Hermione.
- In Panic Room, one of the thieves, Raoul, has this response when they're inside the titular room and protagonist Meg is on the outside, who then proceeds to destroy the surveillance cameras in the apartment so they can't see what she's up to, something that never occurred to the thieves despite hours inside.
- In RoboCop (2014), this is the response of the OmniCorp PR man to the news that RoboCop is investigating his own murder.
- The Famous Five: When George meets Julian, Dick and Anne at the very beginning of the series, she emphasises that she will not make friends with anybody just because they are her cousins, or silly things like that. Julian replies that they don't either, and they might not like her, of course. George looks surprised, as if she hadn't thought of that.
- The Secret Garden: Mary has a moment of this, when thinking why nobody likes her. Martha suggests that Mary does not like herself very much, and indeed she does not; Mary says that she had never thought of that before.
That was an easy joke. I could've thought of it... Why didn't I think of it?
- Played for tearjerker effect in the Dollhouse episode "Epitaph One". The Neural Implanting technology has been weaponized and the United States has collapsed into anarchy after an attack from China. Topher, the scientist who helped develop the technology, is in his Room Full of Crazy and works out how it was done.
Topher: An entire army in a single instant; that's all it takes. That's brilliant! Why didn't I think of that? (sees Adele's expression) Did I think of that? Did I? Oh god... Oh my god... Oh my god...
- In Season 3 of Buffy the Vampire Slayer, Giles is sacked from his position as Watcher and replaced by Wesley, who impresses no one. When Faith meets him for the first time...
Faith: New Watcher?
Buffy and Giles: New Watcher.
Faith: Screw that. (walks out)
Buffy: Now, why didn't I just say that?
- On World's Dumbest..., this is Godfrey's response to seeing people using popsicle sticks to get extra time on parking meters.
- At the beginning of Act 2 in Chicago Velma asks why she didn't think of faking a pregnancy when Roxie doing so got everyone's attention and thus kept her and her trial in the newspapers.
- DICE: The Cube That Changes Everything: Dongtae asks the Final Die why does it obey X instead of doing something for itself. It replies that it just didn't consider it, then determines it wants to see everyone to have a chance to show their wishes and makes X follow own rules.
- El Goonish Shive: Hanma has a Skyward Scream of "I DIDN'T KNOOOOOOW!" when told about poodle skirts during the Goonmanji 2 arc. Nothing worse than missing out on thematic outfits...
- Exterminatus Now has Lothar using an interesting distraction. Indeed, Harold. It's strange.
- In one strip of The Order of the Stick, Belkar and Haley's father Ian release an allosaurus into a gladiator game. As Ian watches the dinosaur attack Tarquin's guards, he wonders out loud why he never thought of doing it.
- From Wacky Races, after the Mean Machine is crushed by a hillbilly's boulder trap:
Dick Dastardly: Wow! What a keen booby trap! I wish I'd thought of it!
- Futurama, "A Biclops Built For Two"; Fry is in a dungeon:
Fry: Leela, you have to get me out of here. It's horrible! Eating scraps, letting my waste drop where I stand like an animal in the zoo.
Leela: Animals go on the corner.
Fry: The corner! Why didn't I think of that?
- Shaggy says this in the Scooby-Doo episode "Scooby's Night With A Frozen Fright," when Scooby shows him how he hooked a link of hot dogs from the gang's picnic basket.
- In an episode of Aladdin: The Series, Genie temporarily gives his powers to Iago, who (contrary to the Jerkass he acts as when an ordinary parrot) goes out of his way to try to improve everyone's lives. After Iago redirects a river, Genie wonders aloud why he never thought of that; Iago uses his newfound genie powers to make a big show opening his head to show off his brain in response. Then all of Iago's benevolence backfires dramatically, showing that maybe it's for the better that Genie didn't ever think of that.
- In Frosty the Snowman when Hocus Pocus suggests to get help from Santa Claus to help Frosty and Karen.
Frosty: That's a great idea. Why didn't I think of that before?
(Hocus glares at him and taps his foot impatiently)
- In the "Flying Sorcerers" arc of Underdog, the King of the Flying Sorcerers has a love of cakes and has Sweet Polly Purebred kidnapped to make him all the cakes he wants. When Underdog rescues her and the king bemoans not getting any more cakes, Polly gives him a recipe so his people can make cakes without kidnapping chefs, leaving the king to wonder why he didn't think of that in the first place.
- In the Darkwing Duck episode 'Jailbird', when Negaduck uses a mystical gem to steal the powers of his fellow members of the Fearsome Five, he uses Liquidator's water powers to part the bay and make a clear path for himself to St. Canard, taking away along with the advantages in his mutation his belief in his own creativity.
Liquidator: Say, why didn't I ever think of that?
- In Teenage Mutant Ninja Turtles (2003), when Professor Honeycutt won't build his Teleportal to help the Turtles return to Earth, fearing it would fall into the hands of the Federation or the Triceratons, Donatello foolishly points out that it wouldn't matter as they could just use a Mind Probe in front of the Prime Leader of the Triceratons.
Donatello: What's to stop them from ripping apart your robot body and downloading the data from your brain?Donatello: Sorry.
- The Sylvester the Cat cartoon "Peck Up Your Troubles," has Sylvester trying (and failing) to catch a woodpecker, As he paces back and forth, he suddenly gets an idea. He holds up a sign that says "Why didn't I think of this before?" then starts climbing a flight of invisible stairs towards the tree branch the woodpecker is perched on. (Second sign: "Anything is possible in a cartoon!")
- In one episode of Ed, Edd n Eddy, after taking Jimmy under his wing and teaching him everything he knows, Eddy sends him out to earn some cash. Jimmy comes up with a clever scam: charging the kids for jumping on a trampoline. Upon seeing how successful the scam is, Eddy asks the other Eds why they never came up with that.
Double D: It would appear the student has surpassed the master.
Ed: But better!
- This exchange from the Danger Mouse episode "The Good, The Bad and the Motionless" when DM and Penfold land at Stonehenge to deal with a disturbance.
DM: Right, Penfold. I'll go investigate; you wait here.
Penfold: (slowly and gradually panicking) Wait here? On me own? In the 'orrible gloom?! WAIT HERE??!
DM: All right, all right. No, you're right, Penfold. I'll wait here and you go investigate.
Penfold: (after a beat) I know, chief. I'll wait here and you go and investigate.
DM: (sarcastically) What a good idea, Penfold. Why didn't I think of that?
- In the "Mooselyvania, Saved!" arc of Rocky and Bullwinkle, upon hearing that Pottslyvania is broke because their treasurer stole their eighty million pazuzas and skipped the country, Fearless Leader is left furious.
Bookkeeper: About the Treasurer stealing the treasury?
Fearless Leader: No! That I didn't think of it first!
- Every episode of Kaeloo is centered around the characters playing a game. In Episode 210, the game of the day is a game show started by Mr. Cat, where the objective of the game is to earn good karma by doing good things. Kaeloo is flabbergasted that Mr. Cat was the one to think of a game where the objective was to be a good person and not her, and wonders out loud why she never thought of this idea before.
- Thomas Huxley's response to Charles Darwin's theories of natural selection was "How extremely stupid not to have thought of that!"
- Shigeru Miyamoto has gone on record saying that he wishes he had thought of and created NiGHTS into Dreams….
- Stephen King was surprised by the Cruel Twist Ending of The Mist, which was based on one of his short stories, and wished he wrote that.