One Friday morning, a blonde named Sai hurriedly went out of her house to check for her mailbox. She opened the door of the box, looked in it, closed back its door, and went back into the house. A few minutes later, she checked the mailbox again, then went back into the house.
She did this again five more times and her neighbour who has been watching her commented, "You must be expecting a very important letter today the way you keep looking into that mailbox."
Sai then answered, "No. I'm working on my computer and it keeps telling me that I have mail."