I absolutely devoured this article. I could identify with every single point - including the summary about the Holocaust. I heard people (under the age of 30) question its validity and it just baffles me that anyone can justify making that statement. What? I'm not sure if you call is ignorance or arrogance but something has gotten in the path between knowledge and assumption.

But back to your list. This is sort of an enhancement to #7. I would love to add one more detriment to good communication. The 'need to know' philosophy hurts more than helps. We have different learning styles and making assumptions about the level of detail I need to grasp the subject might be on a different plane than someone else.  If you're explaining something and getting blank stares in return, that's a pretty good indication that the level of information needed for complete understanding has not yet been reached.