It's funny how people who use the phrase "with all due respect" treat it as if it's a get-out-of-jail-free card to tell you to go f#%k yourself.
I overheard a conversation at the agency I'm working at today, and an account person was on the phone saying, "With all due respect, that absolutely is not what we agreed to and I don't know why you think I'd ever agree to something like that."
It may have been her husband. There's no way of knowing.
I do hope it wasn't a client, vendor, new business prospect or freelancer, because thinking a saying gives you carte blanche to insult someone and actually having carte blanche are two different things.
With all due respect, you're a freakin' lamebrain if you think otherwise.