During your prospect's busy day, you know they will be constantly being distracted.
Usually by an ever growing to-do list, late reports to complete, meetings to arrange, unopened mail, etc.
If only they could spend a few moments to look over your proposal, you know they would instantly place an order with you.
But if their mind wanders even for a split second, your letter, flyer or web content will be passed over without the slightest remorse.