Ok here are a few:
I will try to be nicer if you try to be smarter.
Don’t flatter yourself. I was looking at your friend.
I don’t know what makes you so dumb, but it’s really working.
Stupidity is not a crime, so you are free to go.
If I throw a stick, will you go away?
Warning: I am hearing voices and they don’t like you.
Stupidity is a right but you are abusing the privilege.
Your mouth keeps moving but all I hear is bla, bla, bla.
On your mark, get set, go away.
I would like to help you out. Which way did you come in?