Shut up is pretty much banned from our house as well. Not that it stopes me from using it on the dogs when they won't stop barking.

I'll be honest - I think there's a small danger in tossing insults around like they aren't insults. Get too comfortable with it and you might end up using the terms on the wrong person. And as the saying goes, you get more flies with honey than you do with vinegar. Teasing is fun and harmless when everyone knows it's just teasing, but using terms of actual endearment do a lot for mental health. Negative words, even when used to tease, after a while they accumulate and run the risk of bringing people down.