Usually I say, "Jesus Fucking Christ". Nothing like a bit of good old fashioned Blasphemy when you're under pressure.
If I'm playing Mutliplayer and my friend asks me to do something when Im under attack I often copy a line from Company of Heroes, uttered when you tell them to do something when they're under fire, "A little fucking busy here!"
If I'm playing Mutliplayer and my friend asks me to do something when Im under attack I often copy a line from Company of Heroes, uttered when you tell them to do something when they're under fire, "A little fucking busy here!"