The experts on reading body languages are Psychologist. But we can also read other peoples body language or facial expressions, we just need to be observant on how they react, the tone of their voice or their hand gestures and most of the time we will know if they're angry or happy or disappointed. And I believe this is very helpful in giving appropriate responses to other people, especially if we don't want to hurt their feelings.

Thank you for sharing this @ertwro ! Very educational video indeed! Resteemed!