Someone you wouldn't want as a friend. 

"The Santa Blanca drug cartel will burn to the ground...but know one will know who held the match" -Bowman
"The 6-4 is a family and we'll kick your arse!" -Gates
"We need to work as a team, I need you to survive so that I can survive!" -Dwight Fairfield
"You talk a good talk, but open you up with my rippers and we'll see what's on the inside" -Spectre
"FUS RO DAH!" -Dovahkiin
"I know what yer wonderin' 'what's in the canister?' well.. I'd tell ye... But then I'd have to kill ye. Heh heh heh. I'm only muckin' about, relax. As for what's in the canister... It's best ye don't ask" -Smoke
"You are now entering a contaminated area"-ISAC 
"You're a long way from Texas farm boy" -SGT Pierson
"In this world... IT'S KILL OR BE KILLED HAHAHAAA!" -Flowey
"It's a beautiful day outside, birds are singing, flowers are blooming, on days like this kids like you...should be burning in hell" -Sans
"Want a sprite cranberry?" -Michael Jordan