I've noticed that some people get intimidated by my presence.
Most of the times It's beta males. I sense the nervousness in their throat-clearing sounds for example.
Those people are nervous around everyone they haven't known for at least a year, not just around you. So that's more about them than you.
But it's not my fault if someone feels inferior or something..
Correct!
Is it that my facial expressions change when I'm scarce or my lack of emotions causing people to be puzzled because of the unpredicability?
Could be that I'm incongruent some days. I don't know but It's overwhelming.
I'd definitely say facial expression is a major factor. There is actually a difference in the resting facial expression depending on mood, internally (to you) it's not noticable unless you consciously pay attention to it. When you don't feel like socializing it will show, it's subtle but it will show. Other people are probably not aware exactly why they think it's best to leave you alone, they'll just get a sense that you're not so approachable.
I happen to have been fascinated by this myself and paid attention to it, so I have some insight. At first I just noticed my internal state and how other people responded, then I figured out how my internal state carries through in my observable behavior. It's a subconscious process, it happens without awareness. The realization came on a day I was having a particularly good day, I noticed several complete strangers greet me as they passed, which was very unusual. I didn't get why, I was just walking like I always do, then I looked in the mirror and my expression was different. There was a slight smile, I didn't even notice that I had been walking around all day smiling. It was subtle, but still easily noticable. That's when I realized the link between internal state of mind and external expression.
There are also a few nights I have been out to a club. Most times nothing too interesting would happen, just another night out. A few times though my internal state was different, paid no mind to it until after. Felt like I was supercharged in a way, just overcome with energy in a way I'm not sure I could even control. No effort put into game, no conscious effort put into anything really, I just simply felt great. Women gravitated to me all over the place, some competing for my attention. To this day those experiences are still a bit of a mystery to me, but it changed something in me, it left a mark and a bit of that feeling is always present.
I could try to emulate the behaviors I did in that state of mind, but it's virtually impossible. I behaved differently, that's what all those women saw and apparently got extremely attracted to. They can of course not know my internal state of mind, so logically and empirically the internal state of mind affects behavior. Others observe the behavior and their minds subconsciously reverse engineer the feeling. Ever heard a woman say "I don't know what it is, there's just something about him", this is exactly what it is, they're unaware of how their subconscious mechanisms work.
I have also noticed how when I want to be left alone I don't have to say so, it shows without me having to think about it. People then leave me alone/ignore me and go about their business. I don't necessarily look grumpy, just emotionless and not engaging with my surroundings. I need that sometimes so it's great that most people sense it.
I learned to use this insight to my advantage. To put my focus away from how I look, how I behave and everything external about me and direct it into myself. It takes a lot of effort to control behavior through an entire day, it just takes a fraction of that to bring myself in the right mood. It makes a HUGE difference. I quit doing external game a long time ago to focus on internal game, I do not regret it. In the appropriate state of mind the desired behaviors come naturally and effortlessly.
You can do this too. Begin with registering and becoming aware of how your mood is linked to your behavior which is then linked to how others behave around you. When you've gathered some experiences take a moment to reflect on it and notice the differences. Then if you want more emotional control you can also start to notice your triggers, what is it that brought you to a particular state of mind, if it's advantageous is it reproducible?