This is something I've had a lot of experience with through having had some kind of social anxiety for a long time before I turned around and faced it. This kind of volatility is a function of state and nothing more. Someone who doesn't know you has nothing to go by except what is on your face. When your face is under control, when it effuses the right kinds of emotions, you can achieve some very spectacular effects regardless of whether everything else about you is a mess.
But someone cannot control their face directly. The face reflects the internal state. And anxiety of any kind is the most detrimental social communication that anyone can have. It's only 'useful' function as far as I can tell is as a distress signal, but a public distress signal is essentially an acceptance of defeat and unselective relinquishing of control - probably the fastest and most effective way to signal lower status than the rest of the universe.
People have anxiety for different reasons, sometimes it's due to something happening right now, sometimes it's a habit started decades ago and reinforced through poor behavioural control. Regardless, it is something that must be purged from one's mind completely and utterly.
To be clear, displaying emotion (even negative emotion) can be fine and good. But some emotion - anxiety in particular - is not transformative in the same way anger or grief might be. It doesn't appear to modify a bad situation for the better, it does not 'clean' the spirit and create a natural transition, but is like a poisonous monument to past failure or lack of control. It has virtually no utility for a grown man, and as such it is an immediate differentiator, an indication of inferiority when others perceive it.
The best way I have found to combat anxiety is to transform it first into fear by voluntarily moving toward situations that produce it - that's the main reason I started doing daygame (and before that, kickboxing). Fear is a springboard emotion, it is pure raw material for much more constructive emotional states - I even read in a Scientific American article that determination starts off in the brain as fear, and is processed en route to become something that is useful. But anxiety is toxic and weak, and cannot really be harnessed or used for anything. As such it must be confronted and provoked until it becomes something else, and then transformed.
I don't know if this is the problem for you, but I mention it because anxiety has caused a lot of volatility in my social interactions, and it seems quite a few ladies men have or have had anxiety - probably because its roots come from the particular relationship between a child and his mother. When I see it in other men, it produces a strong, instinctive repulsion that I'm sure everyone feels too. Even when it occurs at very low levels, at the subconscious level, it flatlines seductions and the energy of meeting others and stymies one's ability to create any kind of connection, and especially to establish a dominant or assertive frame.
In fact, something I have noticed is that if you walk down the street and consciously pay attention to those people who did not capture your attention in any way, or if you are at a party and you consciously pay attention to all those people who you never even considered trying to meet, the one thing they all seem to have in common is some kind of latent anxiety or discomfort. So it seems that the social 'brain' already automatically screens out to a large extent those people who exhibit anxiety in public.
I believe that this is why some men who have spent a long time walking a disappointing path in life, who have built up a lot of 'out of date' negative emotion aka anxiety, get so ignored, so little in return for their efforts that they think seduction itself is some kind of scam. That's why any anxiety at all - even a little bit, even when you are a socially capable, likeable person - can very quickly rearrange other people's perspectives of you and shut down your enterprises with them. And it's why those people who are incapable of feeling any anxiety at all have a special capability to draw others toward them that is difficult for the average person to understand.
If anxiety is the problem, it is much better to develop the habit of presenting oneself to difficult situations and seizing control of them in a positive and active manner, enduring whatever happens for good or worse, being honestly introspective and striving to always keep one's spirit (the source of forward momentum, energy, and intent) clean and free of contamination, than it is to allow anxiety to fester and maim one's social capabilities for the rest of their life.