because i'm a cutie pie and the way i communicate it is thru copious amounts of nyehehe teehee ^__^ :3

but more seriously it's because I play a mean villain and people will get all squirrelly and imply maybe I picked up an asshole character because I enjoy acting like an asshole irl unless I go out of my way to be a little cutesy and silly ooc. I don't mind because I am cutesy and silly sometimes but it's also to ward off the "o-omg.... ur so intimidating" comments