What makes you think I'm just going to come running at the second and third knocks. Obviously, I don't live in a large house so it's not like I'm running across my estate to get to the door. Seriously, leave me the feck alone. I'm trying to work and that delightful 5 minute break with you knocking and my dogs barking like crazy is not appreciated. Besides, do you really think I want whatever you are selling/offering at 10 am on a Friday morning.