Avoiding the mailman

Why don't we go and get the mail right away when it gets dropped off? We see the mailman (mailperson, mail delivery person, what's the PC term, now?) coming, we hear them drop our mail in the box, yet we don't go out immediately. We wait... then when he/she is out of sight we crack the door and get the mail. Are we embarrassed that the mailman is going to think we're too anxious? That we're so bored we're waiting around for the mail? That we have no life?