In the beginning of the mission "Suffer With Me" Mason and Woods have just been compromised. Mason's response? "You know what they say, if you're gonna fuck up it's best to get it out of the way early!" The amused and nonchalant tone he uses to express this sentiment says it all, as if to say, "I've been through the shit before, this ain't nothing new."
Woods: Al, this is Dave. Dave... this is your dad!
Hell, just about every time Woods speaks tends to open up opportunities for this. The fact that he's recounting events with surprising accuracy, the grumpiness of someone who's pushing 90 andCluster F Bombs is something to behold.
When old Mason comes to visit Woods:
Woods: Do not enter. [door opens anyway] Woods: I swear to God, I will shove this wheelchair right up your... Mason: ...Ass.
Hell, even after Woods reintroduces David to his dad, he's aware of how "the two broads" are hogging up the space. So he leaves to smoke a cig (despite being 95 in-story).
There is a 'blink and you'll miss it' moment during the epic post-credits music video. During one of the first shots of the crowd, you'll see Viktor Reznov cheering in the crowd. The next crowd shows Reznov and Old Mason dancing in the same shot. Then when the camera returns to the crowd again, Reznov is gone and Old Mason is looking around confused.
David Mason jumping up and down like a fanboy at his first concert, while waving a Cordis Die sign.
Hillary Clinton (actually President Bosworth, but whatever) and David Petraeus rocking out.
Manuel Noriega doing crotch-chops.
Really, the entire premise of Menendez and Woods joining Avenged Sevenfold is hilarious.
Shadows: Hey, old-timer... Are you ready to rock? Woods: (pushes away the wheelchair and stands up) Heh... I'm ready to ROLL, baby! Menendez: What the fuck? Woods: Oh, that shit? Nah, I'm just fuckin' lazy. Now let's go kill this thing!
The fact that Menendez of all people becomes a nervous wreck at the idea of playing music in front of a crowd. The amount of abuse he gets from his band mates might even make you feel a bit sorry for him...just a bit, but...
Especially this phrase:
Menendez: Sarge... I get nervous when I'm on stage. My mind, i-it draws a blank; I feel like I want to throw up. Woods: Calm down, now. We talked about this, right? You gotta let that Cordis Die shit go, man. Take a minute; breathe... you gotta breathe...
A hilarious bit is that he's being a nervous wreck in front of Woods, who he's pissed off at in the main game.
The horse level. Just...just the horse level. To wit, you ride around on a black horse, one-handing an assault rifle or a rocket launcher of your choice, mowing down Russians during the Russo-Mujahideen conflict. Doubles as a Crowning Moment of Awesome, considering you kill around six tanks this way.
If you replay the mission, you can even use a minigun one-handed.
There is a sequence where you fight a group of mercenaries in a stylish night club, in and out of itself fairly mundane but you fight them in slow motion. With dub step music blaring in the background - timed to coincide with your gunshots. It's perhaps the most ridiculous set piece in the entire series and a either a brilliantly meta shot at glorifying violence, or an acceptance by the developers that this is what sets their franchise apart from others.
Then again, the idea of Skrillex blaring as you slo-mo headshot half a dozen mooks is pretty damn awesome.
Though a Leno Device, just the fact that Jimmy Kemmel Live is still on the air well into the mid 2020s and he hadn't aged one bit.
The multiplayer voices, all of them, especially the death screams.
We're WINNING this fight. COME ON! COME ON! I'VE GA-CHYOO! Wanna get paid?! MOVE IT! SHIIIITTTT!!!!!
At the beginning of Karma, Harper can't resist this wishful thinking. Doubly funny if he was burned in the previous mission.
Harper: You know, if this wasn't an op, I believe I could get myself a little hot chick action here. Salazar: You forgetting Pakistan? Your face don't look too good, Harper. Harper: Hey, it's not the face, it's the body they're going to be after.
Harper: Whoa! How you doing, beautiful? Woman/Karma: Screw you, jerk!
In "Karma", there's one for players who speak Spanish. After taking down some Cuban PMCs and accessing the mainframe, you learn reinforcements have found their friends' bodies. One of them can be heard yelling in Spanish "Holy shit! What happened here?"