Some of these phrases do have useful meanings.

To wit:

"As I've said before" = Why TF weren't you listening last time?

"Let's park that for now"= Knock off the obsessing about trivia.

"With all due respect" = You're management, and qua management you're as thick as two short planks, now do as you're told!

I reserve my right to be condescending, sercastic and occasionally outright rude. Generally speaking, I'm dealing with idiots, and life is too short to waste time being nice to them.