"The" thing is

How many times a day do you use "the" in your communications? How often do you have to explain what "the" means afterward?

Unless there is shared knowledge between you and the person to whom you are speaking, "the" can casue confusion and conflict (e.g. "I got you 'the' book." "Yes, but not 'the' book" I wanted). 

Communicating your thoughts clearly will increase understanding, retention, and action on the part of your targets (e.g. increasing chances your traget will buy your product or idea).