There is often a great emphasis placed on the ability to read body language, to know what someone is really thinking even when they are saying something else.
Studies at UCLA indicate that only 7% of communication of feelings and attitudes are via the spoken word while 38% of those messages are with the tonality of our voice, the way words are said (volume, tone, speed). At 58%, the highest proportion of messages relating to feelings and attitudes are communicated via physiology or body language (facial expression, posture, gesture).
With that in mind, it's not surprising that so many people are concerned with interpreting what others are saying with their physiology, and there are countless sources informing us what crossed arms means, making eye contact, expansive hand gestures and many other physical movements.
While it would indeed be very useful to know exactly what others are thinking, both in business and personal life, one needs to be careful not to attach generalised labels to everyone concerning body language.
We are all programmed differently due to unique experiences throughout our lives, creating different internal filters and subsequent responses for all of us. In a professional capacity I would always look to avoid a "mind read" with a client.
Where an awareness of body language can be very useful however, is in establishing rapport. In most situations it is important to connect with someone, whether in a business meeting, social occasion or everyday activities with your kids.
When people are like each other, they tend to like each other! If you are aware of someone's body language and indeed the tonality of their voice, you are covering 93% of their communication with you. By subtly mirroring or matching these characteristics, the person is more likely to be drawn to you, like you or want to agree with you...........now that works whether you're negotiating a business deal, playing with your children, or anything in between!!