That's exactly how body language is misread.
Most "experts" aren't experts. They believe they are seeing something that means absolutely nothing close to what they tell their reader or listener.
Body language takes place, it happens, in a context.
Touching the forehead and then shoulders in church might signify a reference to something greater than the self. On the baseball field it might mean to not swing at the next pitch or steal second.
Pinch her butt at a party and the response will vary depending on whether she pinched yours first or not. It will also depend on whether she finds you attractive or not.
Reading body language is akin to constructing a 1000 piece puzzle.
You first consider all the broad contexts involved.
Is it Christmas?
Are you at the mall?
Is the person crying?
Have they just been struck or were they told their parent just passed away?
You can't read body language without contexts.
The more contexts you have understood the more accurate your reading of body language will be.
Gestures are interesting. We'll talk a lot about them.
But before you even think about "micro-expressions" which almost no one can see in real time, you want to spend a week thinking about contexts.
"If my son was just kidnapped, how would I be reacting? How would most people be reacting? What observable video do you have of people whose children were kidnapped?"
Now you have a starting point for reading body language in a way that will ultimately make you incredibly in tune with what a person is thinking and feeling at many levels.