Haha.. well my kid gets the same reason I was given as a child...
BECAUSE I SAID SO AND I'M YOUR FATHER.
My daughters bought me a special gift, a quirt, normally use for recalcitrant horses. I had it hanging on a wall and merely had to look at it when they got nasty. I never once used it, nor would I have do so, but they always wondered, with nervous laughs how far they could push the envelope. One of them made it a point to see how far she could go to irritate me.