Years ago I had a good client call me to ask if his return was done.  I pointed out that when he was in, I told him that it would be about two weeks before I would have it ready for him and those two weeks weren't up yet.  Then I told him that for every time he calls me looking for the return, I was going to add an extra week to that turnaround time.  I think that was like 20 years ago.  He has never made a similar call since.