That makes sense.
My son doesn't mind NO but does respect it. I usually give a reason like "no, that isn't nice to ..." or "no, that gives ... an owie." ALso, I try to always say please. He knows that's the "magic word."
INterestingly, along the lines of what you just said, I had to yell at the dog the other day and it scared my son. He's never heard anyone yell but instinctually he knows it's not "right."