I think I'm not aware how acutely I am aware of how everyone around me feels (it's part of my "codependency training" as a kid). I have to separate myself from this overwhelming information to make it possible for myself to go through my day. I think this habit is what makes me so susceptible to manipulation.
For example, what I learned recently is that it's important to watch whether a person is in connection to their body. I think that someone who is living only in their head is a serious red flag. It is visible to me whether someone is, why don't I pay attention to it? I remember that movie I saw recently about a psychopath and I realise that what made the actor's play so genius was that he really played this part well, of walking as if he was separated from his body. It's important to look whether the body follows head movements, whether the whole body is coordinated. I think that in narcissistic people the limbs and the torso is somehow disconnected from the head. The body is something that cannot be tricked, that's why they have to exclude it from their consciousness to maintain their false reality. As a result it appears as if there was no human that inhabits the body. When I watch them raise their arm for example, it feels like something is moving but it does not feel like someone is moving something. I don't know why but I used to be turned on by exactly this effect. No wonder I was making such poor relationship choices.
It is important to make a distinction to dissociation. While being dissociated people get outside of their bodies in their heads too. I think that the important difference is whether this disconnected from the body effect happens occasionally or is it there always. Does it happen only in the idle or stress state, or does it even happen when the person is clearly participating in the reality, e.g. during physical exercise. If this body disconnection is a kind of built-in, my theory is that it is a tell-sign of a narcissist.