This "anitcipation" is something to be taken very seriously. When constructing a format for a piece, or writing the piece itself, you must take into account how the reader is going to interact with the message; you need to fully consider how the "total experience" will unfold.
We often hear, "why does it take weeks to put together one piece?" It takes weeks (or months) to put a piece together because you must fully conceive how the experience is going to unfold. Your readers (future customers) don't "owe you anything." They don't need to read a damn word that you write. This is the major difference between a face-to-face conversation and a "conversation in an envelope."
While we may not be able to "control" the experience, we do find that there are ways to garner control over the experience by anticipating how a reader will think, feel, and react to particular information. You must control and act with purpose when choosing every word, every drop of ink, and every pixel you put into your marketing. When these elements converge, profits are born.