Being specific is terrific.

I'd been in and out of Younger Son's bedroom all afternoon collecting dirty clothing and dropping off clean laundry... and also disturbing his studies.
When he'd finally had enough of my interrupting, we had this conversation...

He:  Could you close my door, please?
Me:  Sure.
(I close the door.)
He:  Mother?
Me:  Yes, son.
He:  Could you go outside my room and then close the door?

::snort::