I mailed a letter on Tuesday that will ultimately end up being delivered to a post office box just a few feet from the counter where I gave it to the clerk; yet, I saw when I tracked it online that it has already been in three cities and is scheduled for delivery tomorrow. Meanwhile, another letter that I mailed on Saturday to a location hundreds of miles away was delivered on Monday. How can it take two full business days for a very local delivery and half that time for a delivery several states away?