Body language can offer you a lot of information in every human interaction, if you pay attention and you know how to read it. Much of our interpretation of body language is done instinctively, without our even being aware we are doing it. Still, if you become conscious of what you are doing, you can do it even better.
I have spent over twenty years doing a dance class that has, as a side benefit, been teaching me how to read body language more effectively. I find that I can learn an awful lot by dancing with a person and that this skill translates over into the real world, too. It is interesting comparing notes with other dancers about people we have danced with and what we have learned.
By way of example, I can tell when a person has serious intimacy issues by the way they hold themselves during the dance. There are many other things I learn, as well. I learn who is trustworthy and who needs distance. There are other things I learn that I can’t really articulate now, although I could tell you all about them at the time.