What do you know about body language? I don't mean sign language, but the way a person's body communicates certain things to other's in an interaction with other people. Body language works in conjunction with verbal communication allowing us to get our message across. There's a lot of figures getting around about what percentage of communication is actually non-verbal and to be honest I'm not sure what that figure is. All I know is that body language forms a great deal of what we call communication when we are face to face with people.
I work in a job that forces me to meet new people almost daily and with each encounter a combination of voice and body language is used. We all do it of course. The words we say are punctuated by what our bodies do and in understanding body language, your own and others, one can convey their message much more effectively, and of course, learn many things about the person they are speaking with. The human face is incredibly expressive and can be used to decipher a person's true intent, feeling or emotion despite the words coming out of their mouth. Having the skill, which is not all that difficult to learn, will mean communications are more effective and may even give you the edge in a conversation or negotiation.
As an example the eye direction a person uses in a conversation can be very telling. Looking up and right with the eyes generally indicates a lie or that someone is constructing an image in the mind to use in the formation of a lie. Conversely up and left means a person is recalling a remembered image. There's other tells as well however this simple body-language-trigger is a great one to remember.
There are many body language triggers. How a person stands, what parts of their face or head they touch, how they present their hand for a handshake, how close they stand to another person, where their gaze settles...They all mean things and in unlocking their true meaning a person can deepen their relationships more rapidly and build rapport much faster. It also allows a person to command their own body language and to present better. This is certainly important in a business situation and who doesn't want to communicate better in their personal lives also? Imagine going into job interview for a new accounting role and fist -bumping the interviewer rather than performing a professional handshake. Wouldn't work out so well. Just like in this case there are other useful body language triggers that will pay dividends if known, observed and deployed.
A quick google search will identify many learning resources from paper books, podcasts and ebooks that can help a person learn a little more about body language and with only a small amount of effort one can get greater benefit out of the face to face communications they have. One of the best things I ever did was study body language and it's given me the edge on many occasions. Knowing a person is in-sync with you, open or closed, interested or bored, lying or truthful...Well, it's invaluable. Oh, it's not just in work situations where this works...Check it out.
There's homework too...Reply in the comments what you think the two in the image are saying to each other with their body language. Be creative...I need a laugh.