““Postmen have a legendary aura. A ring at the doorbell may inflame a sense of expectation, suspense, secrecy, hazard or even intrigue. Ringing twice may imply a warning that trouble is on the way or an appeal to make the coast clear. Not all mailmen, though, will ring twice and await an eye-catching Lana Turner, whom they can whisper: "With my brains and your looks, we could go places.” ("The postman always rings twice")””
