I’ve been learning how to read body language and how to alter my body language, and I’m wondering how much of the changes in my body language that I’m hoping to create should be considered honest communications.
Increased eye contact and mimicking a person’s body language seem to be unavoidably genuine expressions of interest. The fact that people can have bad motives for such interest doesn’t seem like it should make me hesitant when my motives for being interested in someone are good.

Posture is harder to evaluate. One function of altering my posture to look as tall as I can is to signal desirable qualities that correlate with height (e.g. good nutrition as a child, leading to good health and a well developed brain). If this led to costly status seeking, I’d feel guilty. But there’s little cost for everyone to match the degree to which I’m looking taller by paying attention to my posture, and little hope that competition for status can be reduced by people such as me ignoring my posture, so I feel negligible guilt.
Another function of posture is to indicate confidence. I’d feel guilty about artificially increasing the confidence I express about a specific factual claim. Most communication is either expressing factual claims of some sort or has no clear content. I’m unsure how to treat the confidence expressed by posture. It seems to say something about some poorly specified anticipated outcomes. Is it mostly a self-fulfilling prophecy, so that it will honestly indicate whether I’m going to be happy in the future even if I alter it in a way that seems artificial? I can’t pin down what it’s expressing well enough to say.

I often hide my hands in my pockets, and that reportedly gets interpreted as saying that I’m hiding something. I suspect this is a false signal. As far as I can recall, when I fail to communicate something that people might want to hear it’s due something like not figuring out whether someone wants to hear it or being too slow to notice a break in a conversation in which to start talking. If I can alter my hand position to better indicate when I’d like people to be more inquisitive about my thoughts, that will improve communication.
Hand movements such as scratching my head that get interpreted as nervousness are more problematic. That scratching does have some correlation with nervousness. I feel a bit dishonest when I hide increased nervousness by consciously resisting my temptation to scratch my head. But some of head scratching habits seem to reflect something other than nervousness (maybe a mild version Dermatillomania associated with obsessive tendencies that fall short of being a disorder), and are probably creating false impressions with most people. I’m unsure whether I can eliminate those false impressions without also eliminating accurate signals.