I bought my first book on body language, back in the early ninety's and it is a subject that has fascinated me, ever since. I would not claim to be an expert, because study of it in depth leads off into areas of anthropology, psychology and the meaning of life, but it is easy enough to figure out the basics.
Approximately 80% of our communication lies in our physical presence. Our stance, the positioning of our arms, our legs, the tilt of our heads, the phoney smiles. Our internal wiring, all those squiggly things inside our heads, are usually way ahead of us, they aready prepared for fight or flight. Its beyond our control. Hence the reason some people speak before their vocal chords get connected to the full extent of their memory banks.
I once watched 16 hours of old black and white interviews with Marlon Brando - mostly waiting for him to answer each question, it must be said, but his replies were well worth waiting for. So too the late Christopher Hitchens.
Intelligent people, take their time to process their thoughts before engaging their gobs, or head butting someone for giving them a funny look.
Fortunately, we have evolved, we accept different cultures, different traditions, even different sexuality. Well most of us do.
But this is about body language. When you find out someone is a bad person, and you didn't know that before, you can look back with retrospect, and see that the all the signs were there. In the 1930's it took a while for the world to catch on that Hitler was bonkers.
Some people have an innate gift, an ability to sum up a person's character, likeability, intelligence within a split second. A little bit ahead of the rest of us. They are able to hone in our base instincts, surpassing intelligence and morality on the way. They go far in sales and spin doctoring. Some go into comedy and parody those quirks of nature, some appeal to the cruelty within us, some use their powers for good.