Not to be a rude, but....

Last early AM anecdote:

The other day I was in a buffet line and someone cut in front and said, "Not to be rude, but I'm just going to take some whipped cream."

That didn't make it any less rude.

Pretty funny phrase, huh? In other words,

"Not to be X (but I will be regardless of what you think, whether you care or not, and it's very obvious that I'm aware of my deviant behavior)."

Common uses: Not to be a pain, not to be a jerk, not to be rude...