Body language certainly conveys some information, but only to a degree. "Experts" basically just created an expectation toward body language and use that as a r

Body language certainly conveys some information, but only to a degree. "Experts" basically just created an expectation toward body language and use that as a reference. For complex emotions this is similar as a horoscope, it fits if you believe in it. This is also why there is "training" for body language. Of course you can "read" the general emotion someone is in.