@LukeAlmighty If I'm in a good mood, I'll just say "However many times I have to say 'No' before you stop asking, can we just pretend I've said it that many times and save us both the trouble?"
If I'm not in a good mood, there are usually four-letter words involved.
I once rendered wide-eyed and speechless one of the cable TV salesmen who used to bug anyone who walked past the electronics section of Walmart. It was rather satisfying.
@LukeAlmighty god how i hate those people...