[moron4hire]

And I have a way of indicating I do want to be interrupted: I leave my door open, I walk around the floor and look for other open doors, I move to the break room and have lunch with everyone else. It would bug the shit out of me if someone interjected themselves into a conversation I was having with someone else in my office.

That's the problem with open-floor-plan. It presumes "my need to know what you're saying/doing is more important than you even getting the opportunity to consent to me knowing."