“The majority of individuals view their surroundings with a minimal amount of observational effort. They are unaware of the rich tapestry of details that surrounds them, such as the subtle movement of a person's hand or foot that might betray his thoughts or intentions.”
Source : Joe Navarro, Marvin Karlins (2009). “What Every BODY is Saying: An Ex-FBI Agent’s Guide to Speed-Reading People”, p.8, Harper Collins