- When Marty leaves the Peabodys' farm, he accidentally runs over one of the two twin baby pine trees.
Old Man Peabody: My pine! Why you...(shoots at the DeLorean, misses and hits the mailbox) YOU SPACE BASTARD! YOU KILLED MY PIIIIINNNEEE!!
- Even funnier when you look at the sign for the Twin Pines Mall (where Peabody's farm once stood) at the end of the movie - it is now called Lone Pine Mall!
- And before that:
Sherman: It's already mutated into human form, shoot it!
Peabody: *fires a shotgun* Take that, you mutatin' son of a bitch!
Marty: Hello? Uh...excuse me? (points behind him awkwardly) Sorry about your barn. (BANG from shotgun, Marty stumbles back and trips)
- And before THAT, the timejump from 1985 to 1955. Crashing into a scarecrow? Funny. Marty screaming at the scarecrow, noticing he's about to crash into a barn, then starting screaming AGAIN? Hysterical.
- When Marty and 1955 Doc go looking for Marty's father.
Doc: Now, which one's your pop?
Marty: (with a grimaced expression, raises his arm, one finger pointed off camera. Doc looks) That's him.
(scene then cuts to Biff's gang surrounding George, mercilessly kicking him as George cheerfully tries to go along with it and begs them to stop, due to a piece of paper taped to his back reading "KICK ME"
Doc: (with a somber expression on his face) Maybe you were adopted...
(Strickland walks in as Biff's gang leave George a wreck.)
Marty: Hey, that's Strickland! Je-sus, didn't that guy ever have hair?
Strickland: Shape up, man! [tears the "Kick Me" sheet off George's back] You're a slacker! Do you want to be a slacker for the rest of your life?
Doc: (dumbfounded) What did your mother ever see in that kid?
Marty: I don't know, Doc. I guess she felt sorry for him when her dad hit him with the car....hit me with the car. (rubs bump on the back of his head)
- "If my calculations are correct, when this baby hits 88 miles an hour...you're gonna see some serious shit."
- And Marty (understandably) freaking out at the car vanishing is hilarious to watch:
Marty: Jesus Christ. Jesus Christ, Doc, you disintegrated Einstein!
Doc: Calm down, Marty. I didn't disintegrate anything. The molecular structure of both Einstein and the car are completely intact!
Marty: ...THEN WHERE THE HELL ARE THEY?!
Doc: The appropriate question is, "When the hell are they?" You see, Einstein has just become the world's first time traveler! I sent him into the future! One minute into the future to be exact! And at precisely 1:21 a.m. and zero seconds, we shall catch up with him and the time machine.
...Wait a minute. Wait a minute, Doc. Ah
...Are you telling me you built a time machine
...out of a DeLorean?!
The way I see it, if you're gonna build a car into a time machine, why not do it with some style?
- Marty McFly first meets his mother as an attractive teenage girl — and immediately experiences a mini-Oedipal breakdown, not helped by the fact that she's obviously into him:
Marty: You're my muhh... you're my muhh...
Lorraine: My name is Lorraine. Lorraine Baines.
Marty: (with an audible squeak) Yeah!... but you're hooonote ... you're so hoooaah, you're so... thin!
- In the process of this, Marty backs off as his mother, completely unaware, makes her advances, before she gets so close that he ends up falling off the bed. Then, Marty's jeans are thrown back at him whereby he falls over trying to put them on.
- Lorraine's never seen purple underwear before. What's even more creepy yet still funny is the fact that Lorraine reads his name as Calvin Klein because she looked at his underwear.
- This also leaves the viewer wondering why the hell Marty wasn't wearing his pants in the first place. Knowing that maybe SHE took them off makes the situation even more hilariously creepy.
- When Biff and his gang are about to slam into the manure truck, they all shout in unison, "SHIIIIIIIIIIIIT!!"
- And afterwards, when Goldie Wilson reaches the car, he takes one sniff and his reaction is one of "Whoo! That is disgusting!"
- "My name is Darth Vader! I am an extraterrestrial from the planet Vulcan!"
- Not to mention Marty using a Walkman with a Van Halen tape as an Agony Beam, and in the extended version of the scene (available on the 25th anniversary DVD) passing off a hairdryer as a brain-melting gun. And the Brick Joke that Marty knocks George out with chloroform, and in the next scene George says he missed school because he overslept.
- Marty's little comment after he tries to get George to ask Lorraine out.
Marty: Jesus, George, It's a wonder I was even born.
- Marty finally meets his Uncle Joey, the future jailbird, who is still a baby at this point in time:
"So you're my uncle Joey. [taps the bars on the side of Joey's crib] Better get used to these bars, kid."
- Near the mid-point of the film Doc and Marty work out how they're going to get George and Lorraine together... only for Lorraine to turn up at Doc's house and tell Marty that a real man stands up for the woman he loves.note As she's saying this, Doc leans forward onto the covered DeLorean in a Head Desk.
- Blink and you will miss it: The DeLorean is equipped with Goodyear tires.
- A deleted scene, viewable in the various DVD and Blu-Ray releases:
You know, this is the kind of thing that could screw me up permanently. What if I go back to the future and I end up bein'... gay?
- Another deleted scene shows Marty peeking into a classroom window and seeing Lorraine cheating on a test. Even funnier is a joke version of the scene, in which Michael J. Fox shows up in a wifebeater, a hairnet, and a cigarette - and acts like a stereotypical Latino thug.
LatinoThug!Marty: Eh, Puto! There she is, mang, there's the bitch! (looks through the window) Cheatin', mang... SUNUVA BITCH, SHE CHEATIN', MANG! (bangs on door) EH, BITCH!!
- Made even funnier when you see that he is visibly cracking up as they film it. And you can hear the crew laughing as well. But Christopher Lloyd amazingly keeps a straight face throughout.
- "My God! Do you know what this means? ...It means that THIS DAMN THING DOESN'T WORK AT ALL!"
- Funnier thing is: It did work, given that he pulled "Coast Guard" (instead of, say, Navy).
- The flaming wind-up car running off the table and setting fire to some old rag. Doc's reaction◊ is priceless.
- This is after he has apologized (quite seriously) for the "crudity" of the model he's built because he hasn't made it to scale or painted it. It is otherwise a large and absolutely flawless model of the area around the clocktower, and as detailed as a miniature film set.
- The part when Marty tries to get directions from the guy in the cafe:
Cafe Guy: *interrupting* Are you gonna order something, kid?!
Marty: Uh, yeah. Give me a Tab.
Cafe Guy: I can't give you a tab unless you order something.
Marty: Okay, give me a Pepsi Free.
Cafe Guy: You want a Pepsi, pal, you gotta pay for it!
- And after that bit, Marty realizes he's sitting next to his future father. After Biff and his gang stop by to harass and torment George, we get a hilarious shot of George staring straight ahead, trying his hardest to ignore Marty as he slowly leans farther and farther forward to stare at George's face with a "holy shit" expression. Not only that, but the shot frames it from the side, where Marty's aforementioned expression is made all the more funny slowly appearing from behind George's straight face.
- Let's not forget the immediate reaction of Marty replying with "You're George McFly!" when George finally cracks. Marty is only able to say that because he'd sound crazy otherwise and the way it sounds makes it so ridiculous because he's already so shocked. What really nails it is George's "Yeah, who are you?" because he has no idea what he's making such a big deal about.
- "Lou, give me a milk! (dramatic pause) Chocolate!"
- And the outtake where the glass slides too close to the edge of the counter, boucing off Crispin Glover's hand and ricocheting to the floor.
- "I'm your density."
- That whole scene is just hilarious. The way he awkwardly approaches Lorraine, holding his notebook out halfway over the table, and then Lorraine and her friends staring blankly at him as he breathes, "Density... has popped me to you." And she responds with a flat "What?"
- Marty explains that the plan to get his mother and father back together worked like a charm, even Biff was laid out in one punch. His father never stood up to him in his life. Doc contemplates this for a moment on how it might affect history, then shrugs it off. Seeing as he was so adamant about not changing history it comes off as "Well serves him right."
- Fridge Brilliance: You could easily point to that moment as Doc working it out that Marty just had HIS life altered via George standing up to Biff, and there were seemingly no dire consequences. So he figures "what the hell?" and pieces together Marty's letter of warning.
- Also Doc sees how pathetic George really was, so he believes it might be for the best.
- The whole Running Gag involving Marty's vest and everyone mistaking it for a life jacket.
Skinhead: The dork thinks he's gonna drown!
- The "Who's president in 1985?" exchange is just outright hilarious because of Doc's hamminess.
50s Doc: Who's President of the United States in 1985?
50s Doc: Ronald Reagan
? The actor
? Then who's Vice President? Jerry Lewis
?! I suppose Jane Wyman is the First Lady! And Jack Benny is secretary of the treasury!
- And later, once Marty shows Doc his 'portable television studio' (camcorder):
50s Doc: No wonder your president is an actor, he needs to look good on television!
- Two words: HOLY SHIT!
- Marty's cover of "Johnny B. Goode": not the performance itself or the EPIC guitar solo, but everybody's reactions to it. The band give him concerned looks and gradually stop playing their instruments as Marty goes into a full-blown heavy metal solo (complete with playing his guitar behind his head, kicking over the amplifier and flailing around on the floor) - and when he is done, he opens his eyes...to see the audience silently staring at him like he's a lunatic. (And Strickland slowly stops covering his ears).
- "ONE POINT TWENTY-ONE GIGAWATTS!?"
- Marty (running after him): "What the hell is a gigawatt?!"
- Doc briefly losing it and yelling at a portrait of Tom Edison.
- "I'm sure in 1985, plutonium is available in every corner drugstore, but in 1955, it's a little hard to come by!"
- Marty is talking with George while trying (and failing) to figure out how to open a glass Pepsi bottle (he seems to be trying to twist the cap off). George finally gets frustrated with watching this and grabs the bottle from Marty, popping the top off with a nearby wall-mounted bottle opener and handing it back to him.
- The Sequel Hook, with Marty and Jennifer piling into the DeLorean with Doc Brown. Watch Jennifer's wide-eyed reaction to it all, and consider that at this point she has no friggin' idea what is going on.
- Huey Lewis cameos as an audition judge, and tells Marty's band that they're "just too darn loud" when they play Lewis' own song "The Power of Love."
- The opening scene. Marty uses a key under Doc's doormat to get into his lab (muttering "Aw, God. Disgusting..." when he notices the bowl full of spoiled dog food), and proceeds to fiddle with different knobs and switches to activate a ridiculously gigantic amplifier - at full volume. Which he is standing right in front of. He gets into position, readying his guitar pick...and is promptly blown across the room by the noise, destroying the amp in process, and crashing into a bookcase. "Rock 'n' roll", indeed.
- Made even funnier when Doc calls afterwards to warn Marty not to use the amplifier.
- Let's not forget the news report at the beginning about the missing plutonium, before we see a ground level shot as Marty walks in and rolls his skateboard across the floor. Three guesses to what's hiding from Marty's view that it hits.
- A blooper version of Marty heading to school at the beginning. He kicks Doc's gate open...only it won't shut again, so he just throws his skateboard at it and runs away. Eagle-eyed viewers can see him starting to laugh as he leaves the camera shot.
- Marty and Jennifer having their kiss interrupted by the "Save the clock-tower!" lady. Summarized best in this gif◊ - just check out the look of exasperation on Marty's face.
- Marty's insistence on George swearing when he opens the car door to 'save' Lorraine.
George: Do you really think I ought to swear?
Marty: Yes, definitely. Goddammit, George, swear!
- Marty's confrontation with Biff. The way he towers over Marty who has just casually tripped him up in the cafe, the camera catching a glimpse of Marty's classically scared face (just watch his eyes) as it happens (the fact that he's barely able to see over Biff's shoulders shows and it is hilarious). Marty then quickly pulls the oldest trick in the book by pointing at something behind Biff, punching him in the face when he's distracted and then taking off. Doubles as Crowning Moment of Awesome.
- It doesn't help Marty's case when he punches Biff, because instead of noticing George, Lorraine gets even more lovesick than before. If you want something funnier, catch Doc's visibly speechless expression as she runs out of the cafe with her friends to the commotion outside where Marty's being chased.
Lorraine: He's an absolute DREAM.
- Marty asking Lorraine's parents where Doc's house is. Since this is 1955, they haven't heard of President Kennedy yet.
- When Marty leaves, Lorraine's parents comment on his behaviour. Irony is abound, whilst Lorraine is staring lovingly after him.
Lorraine's Mother: He's a very strange young man.
Lorraine's Father: He's an idiot. Comes from upbringing. His parents are probably idiots too. Lorraine, if you ever have a kid like that, I'll disown you.
- A shot under the dinner table shows Lorraine caressing Marty's leg. His barely controlled discomfort changes when he abruptly stands up as she pinches his leg.
- Not to forget, Lorraine's rosy gaze in Marty's direction at the same time. His uncomfortable expression nails it.
- In fact, the entire dinner scene. Marty rescuing himself after being questioned about the plot of a brand new TV show and the concept of reruns by Lorraine's younger brother is especially notable.
- Marty's attempting at introducing George to Lorraine all but fails - George leans on the school locker casually but Lorraine is so focused on Marty she simply sees right through him and walks up to him instead. Leaving George awkwardly standing around before walking off.
- When figuring out how to find a social event for his parents to meet and kiss, Marty replies to Doc's question of what they like to do for fun together with a realisation of 'Nothing'.
- Lorraine's execution around the dinner table of her reminiscing of how she met George. All of it. The fact that they met in such ridiculous circumstances makes it all the more funny what with how lovesick she sounds.
Linda: (aghast) That was so stupid! Grandpa hit him with the car!
Lorraine: (firmly) It was meant to be.
- The hilariously awkward photo of Marty, Dave and Linda. Dave's stood there wearing a Mickey Mouse t-shirt and waving like a huge dork, Linda is wearing those ridiculous 80's leggings and that big pink bow thing, and Marty has a half-hearted smile on his face that basically says "I-really-really-wish-I-weren't-here-right-now".
- Doc's penchant for using big words when smaller words could easily suffice, such as calling the Enchantment Under the Sea Dance "A rhythmic ceremonial ritual".
- At the climax of the movie, Marty is about to set off in the DeLorean to get back to 1985. The car, of course, fails on him at this moment. After trying and trying to get it to start up, Marty finally loses it and bangs his head against the steering wheel in a fit of rage - which starts up the engine again. Marty's wide eyes and Adorkable gasp at this is hilarious.
- From a deleted scene, after Marty looks at the newspaper confirming that he's in 1955, an elderly woman bumps into him. What does Marty do? He asks her to pinch him to confirm that this is real. He gets a slap instead.
Marty: (holding his cheek in pain) Yeah, that'll do...