In order to act with kindness towards others we must understand how people work. In fact Rav Volbe calls Mussar "Torah Psychology". Here are some salient points from a book called "What Every Body Is Saying" that I saw somewhere. It also gives us more appreciation of the greatest wonder in all of Hashem's creation - MAN!
People tend to distance themselves from those with whom they feel uncomfortable. They'll lean away, point their feet away or put something between themselves and the other person. They'll create artificial barriers with either their shoulders and arms or with inanimate objects in front of them.
Pacifying behaviors, such as rubbing of the forehead or touching the neck or cheek are automatic responses to the brain's "Please help me feel comfortable again" request. The brain asks and the hands respond.
When you cross one leg in front of the other while standing, you reduce your balance significantly. If there was a threat you wouldn't be able to respond quickly. For this reason the limbic brain allows us to perform this behavior only when we feel comfortable or confident. [I know a Gadol who when speaking publicly crosses one leg in front of the other. He is also a very confident person. Now I see the connection....]
Confident and higher status people claim as much physical territory as possible (with both their body and their things), while less confident people tend to shrink.
The human brain is programmed to sense the slightest hand and finger movement. In fact, our brains give a disproportionate amount of attention to the wrists, palms, fingers and hands. Hiding your hands creates a negative impression, makes people suspicious. [Also, watch out for closed fists. This is a sign that the person is in a battle mindset.]
When individuals carry their thumbs high, it is a sign they think highly of themselves.
Research tells us liars tend to gesture less, touch less and move their arms and legs less than honest people (Vrij, 2003). This is consistent with limbic reactions. In the face of a threat (for example having a lie detected, we move less or freeze so as not to attract attention).