"You're supposed to be guarding the boss's daughter, not screwing her!" "I didn't sleep with her! I mean, yes, I slept with her many times, but..."
The moment the claws come out, the waterbed gets punctured.
Wolverine's brief confusion at his claws not realizing (or having forgotten) his skeleton hadn't been coated with adamantium until sometime after 1973.
When Logan's trying to get past the mansion's door to see Xavier, Hank attempts to stop him, and he teases the younger man with:
Logan: Come on, sure there's not a little beast in you? Come on, Beast. Come on, Beastie.
After Logan gets inside, he says "we're going to be good friends," then sucker punches Beast. Hank transforms into his blue and furry form and chases after Logan. Cue Logan being thrown across the entrance hall screaming.
Charles can't even be bothered to kick Logan out of his home directly.
Charles: This is private property, my friend, I'm going to have to ask... him [Hank] to ask you to leave.
Charles has developed a bit of a potty mouth in the years since First Class, and even gets the movie's Precision F-Strike. Which he uses against Wolverine!
He also dismisses Wolverine's claims as "future shite."
When Logan says they need to find Peter, Charles makes it clear that Cerebro is out of the question. Hank suggests they use a phone book instead.
Wolverine apparently considers Xavier to be a poor driver, based on their dialogue just before they arrive at Peter's home.
Logan: (in quick succession) Here, here, here. Charles: Where? Logan: Stop here, stop. Charles: Alright, alright, alright! Logan: Next time I'm driving, alright, don't get used to it.
And Wolverine is indeed in the driver's seat when they reach the Paris hotel.
When three unknown adult men (Logan, Charles, and Hank) come to Maximoff's house, Peter's mother automatically assumes that her son stole something. Also, none of the trio bothers to correct her when she refers to them as cops:
Ms. Maximoff: What's he done now? I'll just write you a cheque for whatever he took. Logan: We just need to talk to him. Ms. Maximoff: [lets them enter] Peter, the cops are here! ....again!
Hank and Charles have very different opinions about Peter in their first meeting:
Hank: He is fascinating! Charles: He is a pain in the ass.
After Logan, Charles, and Hank tells Peter they're breaking someone out, Peter says it's illegal. Cue the trio looking around the room at all the stuff Peter obviously stole. Xavier then appeals to the teen's propensity for mischief.
Charles: You, you kleptomaniac, get to break into the Pentagon.
Peter's face then lights up like he got exactly what he wanted for Christmas.
When Erik spots Quicksilver disguised as a guard staring in at him through the glass screen in his prison, and the latter flashes an ear-to-ear grin, Erik's expression changes from a mildly interested furrowed brow over the change in routine to a glorious look of "Oh, it's just some freak come to break me out. Charming."
As Logan and Past Charles head through the kitchen, they run into some security guards, and the latter tries to reassure them that they are important personnel. One part of his speech is especially unconvincing.
After Logan loses patience with Xavier's ineffective rambling, the exasperation on his face says, "Oh, fuck this...," and he takes out the two security guards with a frying pan while Charles looks on horrified.
Logan: Oh, I'm sorry. Are you finished?
Magneto, after being freed:
Xavier:[to Logan] Sorry, I'm just not very good with violence. [Elevator doors open with Peter and Magneto on the other side] Magneto: Charles... [Xavier socks Magneto in the jaw so hard he falls over] Magneto:[as he is holding his jaw] Good to see you too, old friend, and walking.
Nearly every scene with Peter, especially the Pentagon kitchen Bullet Time scene.
After he sneaks into the elevator leading to Magneto's prison, he duct tapes the guard inside to the side walls ENTIRELY from TOP to BOTTOM except for the man's nose and eyes.
Peter's delivery of, "Whip. Laaaash."
Which doubles as Fridge Brilliance when you consider that Peter probably often talks too fast to be understood, so he's used to getting an uncomprehending reaction and having to repeat himself more slowly.
Later on, when he returns to the lift with Magneto, the guard is STILL duct taped to the wall. This means the large group of guard reinforcements didn't bother unfastening him and just ignored him in their haste to handle the prison break.
Magneto's little double take over Quicksilver's high-speed clothing change.
Peter acts like an annoying kid when he nags Magneto with, "What did you do, man? What did you do? What did you dooooo? Why did they have you in there?"
When Magneto confesses his involvement in the JFK assassination, Peter turns to the taped-up guard to express his awe, who returns the reaction in kind (with his eyebrows)! Not only that, he mouths Holy Shit as if saying to a fellow passenger, Check this Mofo out. And by "fellow passenger," we mean "guy he just duct taped to the wall."
When Erik and Charles start shouting at each other, you can see Peter squinting at them and then giving the guard a "What the hell is with these two?" look.
His expression when he enters Bullet Time is rather resigned, like he's thinking "Man, this again!"
Bonus points for the kitchen scene in that Jim Croce's "Time in a Bottle" was actually released in 1973.
He just doesn't take the rescue too seriously, taking the time to taste the food and pose the guards in funny positions which eventually will incapacitate them in real-time.
The ending of the kitchen scene is hysterical. All the guards just fall over because of Peter's intervention, while Logan, Charles and Erik just watch with confusion. Then we see Peter waiting at the back of the room in a typically bored "Are we done here?" fashion.
While wearing a hat he stole off of one of the guards.
There's a very tense and uncomfortable silence between Charles and Erik during the plane ride, and Wolverine raises his eyebrow at the two of them in a silent version of "Huh, why am I not the least bit surprised?"
After a heated argument between Xavier and Magneto, the former storms off and the latter looks rather ashamed of what he's just said. Then Logan snarks, "So you were always an asshole."
Later, Wolverine takes note of the mess inside the cabin that Magneto's power had caused:
Logan: Wanna pick all that shit up?
It's worth noting that after the aforementioned line, Erik gives the wreckage now gathered at the front of the plane a look that indicates he even thinks he may have gone a bit far. The transition on Erik's face from contemplating the future that Wolverine could have come from to 'Oh. Yeah. Oops.' is quick, but flawless.
After Erik replies, "She [Raven] was... we were... I could see why she meant so much to you," Charles' facial expression basically reads, "Oh god, he has slept with my sister."
Future!Wolverine briefly panics and loses his connection to his past self... and Past!Wolverine wakes up and finds himself unexpectedly in the middle of the action, in France, surrounded by people he doesn't know and with no memory of how he got there. Charles at first tries to explain what happened, but realizes it's futile and gives this explanation instead.
Charles: ...You're on acid. Someone gave you really bad acid... yeah?
Special mention must also be made to Past!Logan's reaction when he catches a glimpse of a Hulked Out Beast.
Logan: WHAT THE HELL IS THAT?!
When the news of the appearances of the mutants are being broadcast, Richard Nixon and his cabinet are staring in shock at it, and so are Nixon's three dogs.
Beast proudly tells Wolverine that he's rigged up a device to record "all three networks and PBS."
Wolverine:[sarcastically] All three. Wow.
Beast:[not getting it] And PBS.
Xavier calmly performing a Jedi Mind Trick to get past a security guard who asks for ID.
In a Call Back to previousfilms, once Wolverine passes through a metal detector in 1973 without triggering it, he pauses and gives it an amused look. Or maybe a puzzled one — in any case, he's really used to these lighting up like Christmas trees due to his adamantium.
[just before a dangerous confrontation] Beast: I know I shouldn't ask, but... In the future, do I make it? Wolverine: No. Beast:[stares at Logan in disbelief]
When Magneto gives his speech towards the end of the film on live television, we see Ink watching it in a bar, Peter in his basement... and Toad working a mundane job as a frycook.
Mystique shouting "Get out of my head, Charles!" in the climactic scene brought back memories of "The Juggernaut, Bitch!"
Logan's utter confusion upon waking up in the past naked, next to a girl, staring at a lava lamp, on a water bed. And his confusion again when he wakes up in the new future and wanders the mansion until he gets to Charles' study... where the Professor quite grumpily tells him he's supposed to be teaching a history class.
In the same scene, Beast (once again played by Kelsey Grammer) gives him a slyly chipper "late start for you today!", implying that this isn't the first time that this sort of confused meandering has happened.
Near the end when Logan goes to touch the alive and well Jean Grey, he is stopped by Cyclops, also alive and well. Logan is happy to see him, but Scott brushes it off as he would have in the first two movies.
Even better, when Logan tells him "good to see you", Scott gives him a brief "who are you and what have you done with Logan?" look.