I remember from Tiberian Sun, that (in the GDI campaign intro) some of the main characters are involved in a training. A chap surnamed McNeil gets hit (on purpose?) by a teammate's exercise gun. McNeil jumps at the guy, both tumbling onto the ground, and says "You shot me, you son of a bitch!".
Another one from the same game:
"CABAL, define favourable outcome"
"They will all die"
"That will do" (last part of a dialogue between the CABAL system and a Nod commander)
What I like to remember too, is the way the board computer from Samus Aran's suit is saying "Radiation detected" (with a rather nasal voice) in Metroid Prime.
In Htitman: Silent Assasin: "... he is a friend of mine, and has been kidnapped." "A friend? Have you grown soft, 47?" - Agent 47 and Diana during a phone call earely in the game.
Grand Theft Auto 2:
- Someone during a radio interview: "... all such things are happening because people are very-very-much too [breathtaking pause] invuuulved with masturbation." Radio guy: "Oooh now you just sound like my mother, that's just what she says." "I am talking about spiritual masturbation. When you put your haaand on the penis of your soul, and you stroke that penis of your soul..." "Okay, okay, thank you but I think it's time for our next guest".
And let's not forget Metro 2033:
- "Wicked phenomenon, yes? You see, it is not more "evil" than say, fire. It all depends on your point of view. Try to get a better understanding of things before you make your judgement." - Khan (after Artyom's first encounter with an Anomaly).
- In the level D-6, one of the Rangers shouts through the intercom: "People of the Metro! We are the Invisible Watchers!" (and goes on a little longer, though I forgot the words). Another guy named Vladimir interrupts him with, "Ulman, stop screwing around."
- Miller's about being a hero: "... trying to save the world, while being knee-deep in shit, and nobody gives a damn".
- A fellow traveler of Artyom, after reaching Riga station and having a drink to celebrate the survival of the journey to it: "Surely this vodka kicks everyone's ass" (quote may not be completely literal).
- A gun trader about a weapon that he claims to be better than the weapon I have in the same slot as being filled in case I decide to purchase that new weapon: "Throw your junk away, that's for babies!". What is quite funny, because something losing its purpose will of course be recycled somehow in that underground society in which everything is scarce. And that guy says "throw away" in a manner that implicates walking to the nearest trash bin, lol.