ARMOR, the kind of clothing worn by a man whose tailor is a blacksmith.”
― Ambrose Bierce, The Unabridged Devil's Dictionary

There are so many people that walk around with this defensive covering for the body and mind. They have replaced what in earlier times served as protection in combat, by aggressive language and behavior.
 Knowing that this is only to hide the uncertainty and weakness in their personality doesn't help, when the guy is twice as tall as you and instead of asking a question just punches you in the face...