Take a look at Emmet's bookcase during that scene. All the books are Instructions.
One of the pages has a guy being eaten by a shark, but he's still waving with a smile on his face.
When Emmet comes across the Piece of Resistance, he's suddenly states aloud his instinct to touch it as he nears it. Naturally, the movie plays up the dumbness of the situation by having the Piece softly whisper, touch the piece, touch the piece.
Emmet and Wyldstyle stand just outside the doorway to a old western bar. Emmet is told to pretend to be an ordinary cowboy except, well, he's Emmet. He walks in and shouts cowboy cliches and some unrelated sounds including but not limited to, "Bang, bang, zap, zap! Shoot, shoot, shoot! Bullet bullet gun!". Wyldstyle pulls him back outside and tells him to just pretend to be a stool. Emmet walks in, declares he's a stool, and promptly shouts at people to sit on him. He's pulled back out, Wyldstyle tells him she'll show him how it's done, walks in, spits in a nearby spittoon, then everybody loses interests and shifts back to what they were previously doing.
Right after normal saloon activity resumes, somebody yells, "What a lady!"
And while he's pretending to be a stool, Wyldstyle is furiously whispering "Stools don't talk!"
When Emmet falls through the mysterious portal to oblivion, he keeps falling, basically to the point of an implied offscreen Overly Long Gag while the rest of the Master Builders are saving the world.
Emmet: I wanna go home!
(crashes into a house being moved on the roadway)
Emmet: This is not what I meant!
"Trust your instincts."
Emmet's first try at being a Master Builder is putting two flat pieces together then weakly throwing it in front of some pursuing robot cowboys, only for said pursuers to trample over it without even noticing what Emmet was trying to do.
"Unless your instincts are horrible."
When Emmet is taking a shower:
Emmet: Always remember to keep the soap out of your eye-AAAAAAAAAAAAAAAAAAAAAAAAGH!
Emmet getting a glimpse of the real world and remarking, "it's adorable." Then when Finn approaches him, Emmet's instinct is, of course, to think "Don't eat me, don't eat me." What makes this humorous is that this is probably what a sentient Lego would think if he came across a human.
Emmet: DON'T EAT ME! Please don't eat me!
The mention that most Master Builders need to train for years to see "The Man Upstairs", but Emmet's head is so completely empty to begin with he was able to just skip that part.
Lord Business to Bad Cop after he let Emmet and Wyldstyle get away:
Lord Business: It makes me just wanna pick up whoever's standing closest to me and just throw them through this window, and out into the infinite abyss of nothingness!(cue a shot of the black hole below the building) I wanna do it so baaaad!
Bad Cop (nervously): I know you do, sir. Now please, please don't.
When Lord Business first hears about the double-decker couch, he spends the next minute ranting about what a terrible idea it is, even as the scene transitions away from him.
Lord Business' doomsday device has a countdown clock that counts down in "Mississippis".
Even funnier is that when activated, it counts out the first few seconds and then just goes "...and so on."
Lord Business getting attacked in the climax by the most utterly crazy vehicle the Lego citizens have built: An ice cream truck playing annoying music and spraying ice cream at him.
During the scene where we first see his office tower, President Business has his robots surrounding him giving them papers to sign. He ends up getting distracted by one of them and accidentally draws on a robot's face.
Wyldstyle interrupts a taping of "Where Are My Pants?" and throws some pants at the actor — "pants" being "non-skin-colored LEGS".
Wyldstyle: Found your pants! Series is over!
The banter when Emmet first hears what Wyldstyle's name is.
Emmet: What did you say your name was!?
Emmet: W-Wild.... st..
Emmet: Wyldstyle? Are you a DJ?
Wyldstyle: What? No.
Emmet: I-is that your real name?! So.... on your birth certificate, it says Wyldstyle?
Wyldstyle: Let's not talk about my name. (they then get cut off by going into the next world)
Later in the Old West world, Vitruvius is playing the piano in a bar when Wyldstyle tries to make him recognize her. Vitruvius then points out that he is a blind old man, which prompts Wyldstyle to say her name instead.
Vitruvius: I know that sounds like a cat poster, but it's true.
Turns out it really did come from a cat poster.
It's also inherently amusing to hear Morgan freaking Freeman going "oooooh" like a stereotypical ghost.
"Emmet, you didn't let me finish. Because I died."
It's even funnier when you realize that Ghost Vitruvius actually is animated. The movie was done in CG, not actual Legos, so someone had to animate something to appear like a really bad attempt at animating.
Vitruvius trying to sneak around in the Think Tank. He's somehow managed to have gotten several hundred feet up inside of it, and attempts to sneak around a corner over a gap. It goes about as well as you'd think.
Vitruvius' words to Emmet to inspire him one last time to get the Piece of Resistance are uplifting. They're also delivered from a cat poster with the word "Believe!" in glowing letters, with Morgan Freeman's voice coming out of a lazily-animated cat's mouth. It's so absurd that it's perfectly acceptable to laugh even while being inspired.
There's a load of visual gags related to Vitruvius's blindness, such as when he tosses his messenger birds into a closed window, but here are some of the best ones:
When Emmet attaches his head to the wheel and saves them, Vitruvius is going to hug Emmet...but he hugs a pig instead. It's adorable though.
When giving roles for his plan to infiltrate Lord Business' tower, Emmet puts Vitruvius on look out. Cut to Vitruvius 'looking' through a pair of binoculars and announcing that there's no enemies...at a wall.
Vitruvius keeps some messenger birds in his room in case he needs to arrange a meeting with the rest of the Master Builders. How will they do this? Vitruvius explains they will go to an internet cafe and send an email to all the Master Builders.
Then when he throws them through the (still closed) window, they fall apart.
DARKNESS! NO PARENTS! CONTINUED DARKNESS! MORE DARKNESS, GEDDIT? THE OPPOSITE OF LIGHT! BLACK HOLE! CURTAINS DRAWN! IN THE BASEMENT! IN THE MIDDLE OF THE NIGHT! BLACKED-OUT WINDOWS! OTHER PLACES DEAD AND DARK! BLACK SUIT! BLACK COFFEE! YOU GET IT? THAT'S JUST THE FIRST VERSE! DARKNESS! NO PARENTS! SUPER RICH! KINDA MAKES IT BETTER!
The funniest part is that Wyldstyle knows the lyrics by heart and is lip syncing them.
Emmet: Hey, guys? I think we're about to crash into the sun.
Batman: Yeah, but it's gonna look really cool!
(The Batplane smashes through the sun, making a hole shaped like the Bat-Logo.)
Batman manages to land on a police cruiser in mid-air, and rebuilds it into a baby carriage so it falls down!
When the heroes are stuck in the ocean after having survived by hiding inside Emmet's double-decker couch after their submarine is destroyed, Batman remarks that they're basically screwed and that it's not like a ship is just gonna magically appear and save them. Cue Metalbeard and his pirate ship.
Batman just gruffly shouts 'Oh my gosh!' in wangsty surprise mid-sentence.
The entirety of Emmet's plan is this combined with Awesome but notable credit goes to Batman becoming Bruce Wayne to distract President Business. How? By selling him a stereo system - bonus points for also being a Brick Joke and that it actually works.
Bruce Wayne: Cool, what kind of sound system does it have?
Lord Business: Sound system? Ehhmm, we have an iPod Shuffle?
Bruce Wayne: Wait a minute, are you telling me you have a machine to control the universe and you can't listen to tunes in surround sound?
*Bad Cop/Good Cop's head changes to Good Cop's face*
Good Cop: "Hi, buddy! I'm your friendly neighborhood police officer. Would you like a glass of water?"
Emmet: Yeah, actually—
*Good Cop's head changes back to Bad Cop's face*
Bad Cop: TOO BAD!
*Punches glass of water across the room*
Good Cop's cutesy voice is made ten times funnier when you realize that Liam Neeson is doing both voices.
Pretty much all of the interrogation scene between Emmet and Bad Cop.
Emmet: (upon being accused of being The Chosen One) I'm not special! Just ask all my friends!
Bad Cop: Oh, we asked them alright. (theatrically spins Emmet round to face a screen and smacks a button down triumphantly, turning the screen on) Boom!
Guy on screen: That guy's... not a criminal mastermind.
Emmet: You gotta believe me! I have no idea how this thing got on my back!
Good Cop: Sure, buddy. I believe you!
(Good Cop's head swivels round to Bad Cop)
Bad Cop: (motioning stiffly with his hands) Oh, yes. I 'believe' you too. See these quotations I'm making with my claw hands? It means I don't believe you!
And when they tie Emmet to the melting machine, Bad Cop phones Lord Business:
Bad Cop: Hello? Lord Business? I have him right here, sir. We've told him he'll live to stop him trying to escape, but... we're lying to him.
And then later when Wyldstyle rescues Emmet, Good Cop comes casually strolling in with a LEGO croissant.
Good Cop: (cheerily) Hi everybody! How's the melting go-*switches to Bad Cop* Hey, hey, HEY ,HEY!!
Interestingly, many fans found this scene so hilarious that most fanart depicting Good Cop features a croissant somewhere.
Bad Cop's abuse of chairs. Taken Up to Eleven in one scene where they specifically give Bad Cop a chair to kick around for a minute before punting it and dropping it on top of another officer.
Later, we also see a chair fly out of the side of Bad Cop's hovercar.
During the interrogation tantrum, Bad Cop kicks a chair yelling "AGAGAGAGAGAGAGAGAGA!" You're now picturing Liam Neeson yelling it.
While Bad Cop is questioning the cowboys in the saloon on whether they have seen Emmet or not, none of them recognize his face in the wanted poster until Bad Cop draws a cowboy hat on it.
Bad Cop's reveal to Lord Business that all of their attempts to track Emmet based on facial recognition failed because his face is so generic, that it's a 100% match for everybody in the system.
When Bad Cop scribbles a good face with a marker on his helmet, how it looks so badly done, how it moves when he talks, how he continues talking in Bad Cop's voice (only now he's trying to sound higher pitched), and of course there's this:
Benny: *Snaps out of his Master Building daydream* I could build a spaceship!
*No one says no*
Benny: You're not going to say no?
Bad Cop As "Scribble-Faced" Good Cop. Build away, whatever your name is.
Look closely at Good Cop after Emmet gets strapped into the melting chamber, and he looks happy operating the controls. His grin doesn't look like a Psychotic Smirk, but rather the same kind of smile he made when trying to act friendly.
"All ideas are good ideas, except the not happy ones. Those we push deep down inside where we can never ever ever (Moves closer to the screen and then becomes momentarily psycho) EVER (serene again) find them!!!!"
Uni-Kitty serves as a distraction in one of the funniest scenes in the movie.
Batman: Left the weird cat thing to stall.
Uni-Kitty: *Prancing around on the meeting table* Business, business, business. Numbers. (whispers) Is this working? Robot: Yes. Uni-Kitty: YAAAAAAAY- (Smash Cut)
While infiltrating Lord Business' headquarters, Metalbeard reveals he can transform into a copy machine. However, a pair of guards decide to use it to photocopy their butts on it, causing Metalhead to destroy them. He explains that one of the rules of being a pirate is that nobody is allowed to put their butt on a pirate's face.
Metalbeard is, if not actually undead, a Frankensteinian creature rebuilt from only his head and organs. And a robot. And a pirate. And as shown when transforming into a comparatively tiny copy machine, surprisingly good at stealth, not unlike a ninja. He's literally a Ninja Pirate Zombie Robot!
The funniest part is some of the closeups of Benny when he screams "SPACESHIP" - trance-like and maniacal at the same time.
Benny tries to tell the Octan Corp computer to lower the laser shields so Emmet can get the Kragle, but the computer keeps reading his input codes wrong, and at one point, even talks like he's ordering moviefone tickets!
Benny: Cool, Talking Computer! Please disable the shield system!
Computer: Of course.......There are no movies in your area with that title.
And when does the computer finally lower the shields? When Metalbeard speaks like a pirate.
Metalbeard: Be ye disabling of yon shield?
Computer: Disabling shield.
When Metalbeard moans about losing his once "strapping and virile" pirate body to Cleopatra and The Statue of Liberty, they're cringing. Looks like his attempt to impress the ladies didn't go too well.
Metalbeard's crew consists of him, a Pirate wench, his first mate and a Magician, Speed Racer, the Flash, Disco Guy, a Witch, a Mime and a Gorgon.
We have this scene when Metalbeard rescues our heroes from being stranded at sea.
Benny: Metalbeard? I thought you said we were a lost cause!
Metalbeard: YE ARE! Did ye not hear me whole story circumscribing the folly of this whole enterprise?
Batman: It's kinda hard not to hear when you're yelling everything...
Benny's face when he's flying into the Octan Corp building with Batman. During the whole scene he's just grinning happily.
Metalbeard randomly transforming into a folksy robot and singing a Judy Garland song. Uni-Kitty was terrified/disgusted!
Also considering that when the Barista is interviewed a mere day later, the price of coffee has increased to $42.
The interaction between Superman and Green Lantern, with the latter constantly fanboying over his hero and the former being annoyed to no end. Their universe takes advantage of this, producing one of the funniest lines in the film's penultimate climax:
Superman: (After being placed in the Think Tank) At least it can't get any worse....
Green Lantern: Oh HI Superman! Looks like we're going to be neighbors!
Superman: Does someone please have any Kryptonite they could give me?
(Superman is stuck in gum)
Green Lantern: Don't worry, Superman, I'll get you out of there!
Superman: No, don't—
Green Lantern: Oh, my gosh! My arms are stuck! My legs are stuck as well!
Lucy hijacks the camera that was filming "Where Are My Pants?" to tell all the Lego worlds what Emmet's done through huge, mounted monitors...we cut to Middle Zealand, and find that they're only listening to a messenger on horseback reading what she's saying out of a scroll! In falsetto!
In The Old West, everyone has stopped trying to kill each other and is listening to a phonograph to hear Lucy's speech. Then a cowboy takes "break the ground" a little too literally and starts trying to pull up the floorboards.
And he succeeds! And everyone cheers!
"Where Are My Pants?" is funny on its own just for the utter silliness of its one-joke premise and the actor's head-spinning as he asks his wife the titular question. Not to mention how that alone gets Emmet to burst out laughing.
In an easily missed joke during the climax: "The Man Upstairs", while fixing everything with crazy glue, removes the actor's pantsless leg pieces and glues a pair of pants'd legs to his torso. Guess he won't be losing them again.
The ending. William Shakespeare starts doing the worm.
Abraham Lincoln zooming into the final battle on his chair, with Shakespeare and Gandalf hanging on.
When Vitruvius announces that Lord Business plans to end the world, Cleopatra tries to kill herself with her asp and Michaelangelo hides in his shell.
Also, the shot of the Dragon putting two pieces together in awe and wonder.
In a blink-and-you'll-miss-it moment, when Emmet, Wyldstyle, and Vitruvius get knocked off of their wagon and land on the train, the pig that was riding with them misses the train completely and explodes into sausage links.
In another blink-and-you'll-miss-it moment, Chewbacca is holding one of the oversized turkey legs, before switching it out to a wrench.
After the climax and the Man Upstairs agreeing to let Finn actually play with his large collection of sets, we get the best Sequel Hook since Toy Story- "And since you can play here now, so can your sister." Cue a Flat "What." and without missing a beat, a cut to the LEGO world where a massive pink spaceship appears... and beams down Duplo creatures bent on destroying the Master Builders, followed by an Oh Crap and credits.
Double Points for being made with the much hated toddler Lego.
Triple Points for giving the Duplo alien the voice of a toddler girl, most likely Finn's sister.
Given without context, because it's a huge spoiler otherwise, but this one line sums up LEGO so well.
"But the box says '8-14 years'!"
"It's the recommended age. They have to put that there."
"This is not a toy!"
When Finn says he "accidentally" took the top off the Octan Tower, The Man's reaction is priceless.
The Man Upstairs: You accidentally, expertly, CAREFULLY took the top off that Tower?
Meta and Out of Canon
The various names given to the human artifacts are often funny, especially the Sword of X-Act Zero (it's an x-acto knife blade).
The Poleesh Remover of Na'iil. It's just nail polish remover. And an old band-aid (aka the Cloak of Ban Da'id), which Lord Business hears is very painful to take off.
And who could ever forget the Fleece-Crested Scepter Of Q'Teep?
The fact that the names of the worlds that appear when the characters enter them are part of the world itself. If you look in the background after Emmet and Wyldstyle enter "The Wild West", you can see the words "The Wild West" still floating behind them.
A lot of the sound effects are lazily done on purpose making them comically brilliant and are definitely worth a giggle or two.
Emmet's neighbor has a lot of cats voiced by people just going, 'Meow' in a high note, except for the last cat who has a deeper voice.
In the Old West, the soundtrack is accompanied by a high-pitched voiced going, "A-Yah" and "A-Yah-Yah" whenever the robot sheriff and his deputies are staring down Emmet's wanted poster or the heroes themselves.
The LEGO pigs themselves are even saying straight up, "Oink oink oink", and it wouldn't be much of a surprise if the same guy voiced all the animals and even some of the extra characters.
The pigs make for an utterly hilarious gag when Emmet and Wyldstyle are fleeing in The Wild West. Wyldstyle starts to build a vehicle for them as Emmet runs wild getting tangled up in wire and pigs. As they reach Wyldstyle, she grabs the wire, snaps it in the air and suddenly all the pigs get in line like goddamn sled dogs with one synchronous "OINK!"
Several times throughout the movie, when ships start moving their motion sounds are exactly the sound a person would make if they were imitating a plane.
The Micro-Management robots sound exactly like someone pretending to sound like an evil robot.
Blue skies! Bouncy springs! We just named two awesome things! A Nobel Prize! A piece of string! You know what's awesome? EVERYTHING!
Then there's the "MTV Unplugged" version of "Everything Is Awesome" at the very end of the credits.
The entire third trailer is basically one big Parody of the Man of Steel trailer, using the same music, referring to Emmet as a 'Man of Plastic' and ending with a Lego-Superman commenting aside:
Lego Superman: "You ruined it. Good job."
In the Behind The Bricks trailer, there's a scene where Good Cop and Bad Cop argue over who is the lead in the film. It's funny enough, but pay attention to what is going on in the background instead, and you'll be laughing much harder. A mini figure is trying to wrangle some chickens when one pulls a GUN on him. The next seen then shows said mini figure lying on the floor while the chicken pins him down with the revolver and another chicken steals his cash.
One shot from the party scene mentioned above is really funny. Pause when Emmet walks in and the shot comes into focus, and you'll see Bad Cop and President Business are holding Vitruvius upside down to do a keg-stand, Wyldstyle and Batman are doing karaoke on a table, and- this is the good part- Uni-Kitty and Benny have what can best be described as alcohol bottles up to their mouths. In addition, there are a ton of bottles and cups all around on the floor.
"Oh, no, those weren't pranks. I was legitimately trying to destroy them all." "WHAT DID HE JUST SAY???". And then the entire main cast stops what they're doing and glares at President/Lord Business. With Bad Cop about to throw a chair and Batman hanging upside down and glaring.
"...weird unicorn cats." Gilligan Cut to a confused Uni-Kitty (cleaning herself) asking, "Who said I was weird?"
Vitruvius talks about how he's voiced by Morgan Freeman, and then talks about how Morgan could make reading the phone book sound interesting. And proceeds to do just that.
Also pay attention to the boom mic operator, he looks like he's in a state of pure bliss during the phone book reading.
Vitruvius: "555-3492... Mmmm... just listen to those rich molasses."
When President Business is complaining about being voiced by Will Farrell, after he puts his shirt back on, the camera jumps back and you can see he's wearing Wonder Woman briefs. (Where are his pants?)
"They're shooting at us. With real lasers." "And blowing us up, to be reassembled!"
Other amusing background antics:
A stagehand talks with a female stagehand and then laughs. Whatever he said prompted the female to get angry and pour her drink all over him and storm off.
A horse attacks a crew member and they land off-screen.
Abraham Lincoln talks on a cell phone!
A technician works on overhead beams and then falls down.
During the first scene with Metalbeard, a stagehand is brushing his shark-arm's teeth.
A mermaid tries to move around the set without having legs. One time she even falls forward, gets up, shakes dirt off her arms, and continues.
Batman, angry, intimidates a crew member by lifting him up by his throat with both hands and shaking his head, as if to say "You don't mess with the goddamn Batman!"
And of course, Benny.
Benny: We got a space dog, a space cat, space chair, space shelves, uh, I think there's some space food, astronaut ice cream, we have astronaut milk, uh uh SHELVES, DID I SAY SHELVES!?
Batman: So they [the directors] got Will Arnett to voice me. Guess that means Clooneypassed.
And President Business:
President Business: You'd think for a characters as important as President Business, they'd be able to get someone with serious chops. You know, I'm talking DeNiro. Pacino. Ryan Gosling. (shirt comes off, wolf whistle) Cuba Gooding Jr. But no! They get Will Ferrell? When you're scraping the bottom of the barrel, you find yourself with a Will Ferrell.
In the background, Vitruvius blasts Abraham Lincoln away with a bolt of lightning after Unikitty mentions "no government".
Batman and Emmet are taking a break between takes on the pirate ship set, and Batman says he'd like someone to invent arm-rests. ... like, not the chair, JUST the arm-rests! That he can take to a concert....
The Running Gag of Batman's grappler repeatedly malfunctioning.
The music video for "Everything is Awesome": Instead of showing Tegan And Sara and The Lonely Island in person, the creators of the video made minifigures of them, stuck them to pencils, and wove them around in front of the camera.
The line "Everything is better/When we stick together" gets accompanied by a Visual Pun of Tegan and Sara taped to each other.
One of the Lonely Island members gets dipped in chocolate frosting, then cleaned in a fishtank, only to get dipped in frosting again later in the video.
The "Enter the Ninjago" clip from the Blu-ray bonus features. All of it.
"Kids love ninjas. It's a sad fact of life."
Having been shown several clips from his movie with Lloyd the Ninja edited in crudely, Emmet gets annoyed, giving us this exchange:
Emmet: Okay... but at the end of the movie I still save the day, right? Like how it actually happened in my actual, real life?
Hollywood Guy: You know, you'd think that after two examples your expectations would be lowered already. But if they're not... LOWER THEM MORE! (shows another movie clip with Lloyd the Ninja saving Emmet from his Heroic Sacrifice fall, and letting him land safely on a horse, causing a chain reaction of falling horses that ends with a squeaky panda)
Hollywood Guy: Yeah, we had to put that in there for the international audience. Turns out, they don't love words! They love pratfalls, slapstick, physical comedy, and cute furry animals.
Emmet: Instead of making my life story, why didn't you just make a whole movie about ninjas?
Hollywood Guy: What a great idea! The Ninjagos!
The rise and fall of The Super-Crunchy Ninja Skateboard Party Movie With Pratfalls Slash Physical Comedy And Cute Furry Animals For The International Audience:
Announcer: Warner Bros. presents the The Super-Crunchy Ninja Skateboard Party Movie With Pratfalls Slash Physical Comedy And Cute Furry Animals For The International Audience! (then, whispered, in Rattling Off Legal style and becoming increasingly inaudible) The international audience includes the UK, Australia, and other English-speaking territories not part of the continental United States, Alaska and Hawaii. (Smash Cut to Emmet's utterly bewildered face) Coming soon to a theater near you! (Smash Cut to black screen with text, with wind playing in the background) The Super-Crunchy Ninja Skateboard Party Movie With Pratfalls Slash Physical Comedy And Cute Furry Animals For The International Audience was the biggest bomb in the history of cinema. The Studio lost all their money, they tore down Hollywood, and no-one ever made a movie again.
Bonus points in that this all takes place across about 15 seconds.
Lord Business: Behold, the Giant Micromanager! ...And I know that technically that means I should just call it a Manager, but that doesn't sound as terrifying.
The characters "auditioning" for the movie, which can be viewed here.
All the characters have good moments here; Emmet trying various takes of "I don't know what I'm doing" (including a 'fat guy' take), Wyldstyle listing the body parts of the robots she's killing, Good/Bad Cop being told they can't be in the movie together due to 'union issues', and let's not forget Lord Business complaining about the poor acting.
Lord Business: OK, guys. What I like is when you bring the laughs... so let's see it just FOR ONCE!