Sarcasm, used mostly AS sarcasm nothing else.
For example:
Dude: Are you really a cat?
Dudeno. 2: Surreee, of course I am!
Dude: Im going to beat that dude up!! GONNA BLOW HIS THING!
Dude no. 2: Surrreeee..
See, dude no. 2 is smart. He knows that Dude cannot blow up his thing because thats like, a crime.
TERRORIST