I'd have to say I've come across this problem myself.
And I must say, E.C., you're pretty accurate about how people see you. I mean, we've exchanged barbs nonstop for the past what, six years? I always thought of it as witty banter and such. But alas, I sympathize with your dilemma. No matter how many times I slap someone with the white-hot intensity of 53,486 menopausal Joan Crawfords, they just smile and laugh, and call me silly.
Dammit, I wanna be evil too.
See, the problem with being cute and clever is that nobody really ever takes you seriously. If I were to hide in a darkened room with a gun (loaded with blanks, of course) and fire the thing inches from my roommate as he walked in the door, he would look at me and smile. Then he would offer me a beer. In my experience, this would not be considered to be an appropriate response to evil.
This whole train of thought has driven me to wonder if there are, in the world of comic books, Superheros who dream of nothing but being the villian. Even as they save the day, they secretly have this burning desire to kidnap the beautiful secretary and lock her in a closet while they rob a nearby bank (blowing it up afterwards, of course). Maybe deep down inside, even Spiderman wishes he could be evil and nasty and cruel. Because let's face it folks, the truly evil, twisted, malificent creatures out there are the ones we can't stop thinking about in our dreams.
But no, we're good guys. Whether we want to be or not, that rosy bitch we call fate decided we get to be funny and cute. Life is so unfair.