In the pilot, after he, Penny, and Brain are dropped out of a skiing gondola, Gadget summons his Gadgetphone out of his hat to complain about what had just happened.
Gadget: I'm calling the maintenance department! This gondola probably hasn't been serviced for months!
Gadget's last bit of advice in the end of episode segment? "Never bring your dog to the ski slopes."
Brain's instincts kicking in when Gadget attempts to throw away a torch made of dynamite, leading to an impromptu game of fetch that ends with Gadget proclaiming that he has everything under control right before it detonates in his hand.
Yet another: One of Claw's weapons is a smokescreen deployed from the rear. He tries to use it on Gadget, but Gadget clamps it shut, causing the smoke to pour into Claw's cockpit. Thinking his foe is on fire, he then deploys the snow-gun. All while being blissfully unaware that it's Dr. Claw.
Gadget's horrifically bad attempt at flying a rickety airplane in "Photo Safari," starting with this exchange:
Penny: Are you sure about this Uncle Gadget?
Gadget: No problem, Penny! The nice mechanic said any fool could fly this plane!
And fly it he does. Upside down, sideways, through buildings and nearly into the ground, all before leaving the runway area. What really makes it hilarious it is Penny and Brain's shell shocked reactions, though - while Gadget's whistling and singing, completely oblivious to the danger they were just in as usual, Brain's freaking out and Penny frozen to her seat looking like she's having trouble not joining him.
The episode "Quiz Master" has a funny bit where a M.A.D. agent disguised as a bearded caveman in a stovepipe hat tries to waste Gadget, only for the bumbling detective to avoid the attack and say "Sorry, Mr. President".
This exchange from "Gadget's Clean Sweep".
Dr. Claw: You must get the Crown Jewels. I wanted them since I was a child.
Thelma Botkin: You were a child?
In the "Volcano" episode, Gadget's following Brain, who is disguised as a hula girl and gradually shedding the disguise. By the time Gadget finds the skirt, the look on his face is absolutely priceless.
The M.A.D. Agents mistaking the real Gadget for his robot duplicate in "Doubled Agent", especially when Hilarity Ensues once the real Gadget asks the agents if they can stop for ice cream.
The second episode featuring the Great Wambini and the Lesser Wambini has the Lesser Wambini attempt to stall the rich pet owners at the phony seance by doing shadow puppets. When the Great Wambini hears the cops coming and drags his assistant with him to their escape, the Lesser Wambini is still doing shadow puppets and is apparently oblivious of what is happening around him.
"The Infiltration" has Gadget confronting Presto Changeo, each insisting that he's the real Gadget. The real Gadget stands near Chief Quimby, and then Gadget's mallet activates by itself and bonks Quimby on the head. Needless to say, this helps Quimby Spot the Impostor:
Quimby: (Pointing at Presto Changeo) Arrest that man! (Points at Gadget) This has got to be the real Gadget.
Gadget's Leitmotif playing as Quimby says this makes it all the funnier.
The end of episode safety tip has Gadget talking about the dangers of bad parking. He notices a van blocking the road, and criticises the driver. He has to be informed that it's the Gadgetmobile, and he can't remember parking there.
(Macho Miguel finishes climbing the cliff side, and stops to catch his breath.)
Macho Miguel: Huh?
(Mariachi band, standing on the cliff, starts playing MM's theme again.)
Macho Miguel: How did you get-
"The Japanese Connection" had some pretty funny bits:
M.A.D. Ninjas: Konichiwa, Gadget-san. We are about to do away with you!
Gadget: Ah so!
Later on in the episode:
Sumo Wrestler: Ohayou!
At the end of "Did You Myth Me", after Dr. Claw's plan to obtain a formula to turn lead into gold is ruined, we find out that he had gotten too ahead of himself and had begun stocking up on lead, and now his castle is filled with piles of huge lead bars! For extra hilarity, the M.A.D scientist who was leading the operation had discovered that the formula didn't turn lead into gold, just changed it to the color of gold, meaning that his plan was doomed from the start, and Dr. Claw would've been stuck with tons of worthless lead either way!
Gadget: Whom I expect could be our arch-nemesis, Dr Claw, using a clever alias!
"I don't know the meaning of the word capitulate! However, I plan on looking it up."
The brief Scooby-Dooby Doors sequence that occurs during the opening car chase, only for the Gadgetmobile to suddenly be alone in the street. There's a beat just long enough for Gadget to look around in confusion before the MAD agents speed past again.
Gadget's reaction to Gadgetmobile hitting a pothole while he's trying to climb out using his Gadget Suction Cups. He ends up standing on the side of the door.
Quimby, angry over Gadget's continual upstaging at the hands of Debonair, is then bewildered that Gadget is hoping for a Crimie Award for Best Crimefighter, despite his job being on the line.
Quimby: What do you, of all people, need a tuxedo for?!
After realising that Claw escaped with the transformation formula, Gadget immediately thinks he's taken Chief Quimby's form and arrests Quimby. After being fired and nearly destroyed, the newly reinstated Gadgetmobile is in no mood to help him out.
Quimby: You can run bioscans, voice comparisons! Prove I'm the real Quimby!
Gadgetmobile: Talk to the steering wheel, because the engine ain't listening.
While Gadget is battling the evil Robo-Gadget, hanging over the edge, holding on by his tie:
Robo-Gadget: Hey, Gadget, it's a clip-on!
"Somebody's been watching too many Saturday morning cartoons!" Cue Gadget, Claw, and Kramer looking at the camera.
This is followed by a shot of Sikes shaking his head and going "Huh?"
And how can we possibly forget the part of Inspector Gadget's training session where his guru tells him to focus completely upon "obtaining the balls." More specifically, a pair of balls on the floor in front of him. Gadget's cybernetic hand extends as desired...and then it keeps going, rocketing straight at another pair of balls...
[The Guru screams like a little girl; cut to the observation room, where the onlookers wince in sympathy] Guru: (In the highest-pitched voice imaginable) Ungrip! Ungrip! Turn it off! TURN IT OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOFFFFFFFFF!!!!!!! Chief Quimby: Well, I guess six million dollars doesn't buy what it used to. Brenda: Excuse me. [As hospital workers put the guru in an ambulance, with an ice pack on his crotch] Guru: (Still in the highest-pitched voice imaginable) He is not a man, you know. Oh! He is a monster! (Sobs in pain)
After a captive Gadget asks why Claw is creating robots: