Yet it's fascinating, and for me perhaps unintentionally useful. Almost a mindfulness technique. Because you see I was sitting in Stalagmites one night with Shona when she pointed out that we were mirrored and thus getting along and attuned to one another. It is freaky to have it pointed out to you that you have subconsciously adopted each others limb arrangements etc.
Anyway, since then I've been freaking friends out during conversation by noticing we're mirrored. It's been probably two or three years. But it turns out it serves the function of bringing me into the present moment.
And that's useful for me to disrupt activated states, except maybe flirting which I don't want to be too conscious of.
But is it of any use in predictive power? For example if you read Bill Clinton's body language during his public broadcast in which he denied sexual relations with Monica Lewinsky, could you actually say anything at all? Or if you watched the micro-expressions of Angelina Jolie standing next to Brad Pitt at the press tour for 'Mr & Mrs Smith' did you know anything?
Because every (and the only) documentary I watched on body language, has body language experts 'reading' events that we already know how they panned out. I very impressive demonstration on how to retrospectively predict from the past with knowledge of the future.
Like listening to 'analysts' talking over a sporting match. I suspect much of the 'knowledge' actually doesn't and can't come into play in any useful way.
I think thusly body language is best in it's predictive power when left intuitive and imprecise. Which is to say for betting. Presuming certainty in the unknown.
You don't know what Bill Clinton is lying about, you just know he's lying (though probably a poor example because his denial was so specific). You don't know what's going on between Brad and Ange you just know she finds him attractive.
And I was advised and likely agree that you don't need to read up on body language and how to descifer it, because language works because it is understood by the recipient. Don't pay attention to the body language, pay attention to how you feel afterwards.
That said, I don't think knowing that tugging on the ear lobe indicates somebody doesn't like what they are hearing is bad, it can be the kind of thing that alerts you something has triggered you and you've turned hostile in the conversation, the person feels under attack.