I'm standing behind the front door, waiting for pupil to arrive. I see through the glass the postman stand in front of the door and, without bothering to ring the bell, start to push a failed delivery card through my letter-box (here's one we made earlier...). So I run to open the door and shout at him that I'm in. He shouts back not to shout and I shout something again, he steps in and shakes his fist and I tell him (perhaps in a loud voice..) that he's trespassing and to get out.
Now, falling out with your postman is not a healthy thing to do and I'm worried if I will ever get mail again :O