He Thinks He Knows it All
In an attempt to appear "professional," many people overshoot the mark and come off as being arrogant, officious, disingenuous, and rude - all of which undermine, rather than bolster, a person's creativity.
The Importance of Being Earnest
Arrogance connotes self-importance and an inflated ego, and is often the result of a person attempting to overcompensate for their self-doubt. However, arrogance does not convince others that you are superior to them, but rather that you are self-important: you are acting in your own self-interest and cannot be trusted.
Verbal Communication
Be careful about your choice of words: avoid using "I" too much, and be careful of phrases that denigrate anyone who would disagree with your opinion.
Use qualifiers to tone things down. While overusing words such as "probably" or "maybe" or "might" make a person seem unconfident, avoiding them altogether can have the opposite effect. Also, avoid extremes - saying that something is "certain" or "inevitable" or "absolute."
Its' also important to be respectful when listening, especially if you disagree with someone - make sure you understand their point. It is often better to ask them questions to lead them to consider your point of view rather than to be confrontational ("you're wrong").
When its' necessary to argue, be careful to isolate the issues from the people.
On tone of voice, speaking very slowly or emphatically suggests that you think your listeners are unintelligently. It's a matter of balance: you don't want to seem to be rushing through your speech, or speaking in a monotone voice - but if you are too slow, too lilting, you seem like a kindergarten teacher.
Nonverbal Communication
Nonverbal communication is classified as illustrators (gestures that mime things that you are saying) and emblems (gestures that convey emotion or are used for emphasis).
As with tone and pace of speech, gestures can be overdone. The author doesn't provide much guidance, except to suggest using new programs as a model.
Your posture and expressions can also communicate disdain or disinterest, but the author is not specific.
When Listening
What you do when you listen to another person is often more expressive than what you do when speaking - it provides cues to your reaction to the other person.
The author speaks of certain specific behaviors that other people find dismissive: being overly casual in your posture, being completely stoic, nodding too often, failing to maintain eye contact, repetitive hand motions (drumming your fingers), rocking back and forth, doing other things (checking your blackberry), crossing your arms, etc. the list is random and descriptions brief, and he doesn't indicate what better practices would be.
A Final Word About Character
The author uses this section as an opportunity to cram in a few words about character in general. He refers to the ten commandments, to suggest that a person who harms others, is unfaithful to a spouse, steals, lies, etc. will have character issues that harm their credibility.
EN: the mention of religious doctrine seems suggest that only those who conform to ethical principles of a particular religion (in this instance, christianity) are trustworthy people. There's some irony in expressing such a smug and self-righteous sentiment in a chapter about arrogance, and it's a mindset that is contrary to multiculturalism - but a good point to be taken that many religious individuals are bigots and even those who profess to be open minded still implicitly (or sometimes explicitly) expect (or demand) that others adhere to thier own religious beliefs.