In my experience there is two groups of people. The first is the group that can kinda tell there is something legit about the spiritual stuff but can't really see it. The other is the people who can see it. From my experience it's usually caused by trauma.
What happens is that the subconscious mind creates the environment for the consciousness to work in. The consciousness can't handle a complex environment with a lot of variables, so the subconscious has to 'dumb it down' in a way. The way it does this is by filtering out everything that isn't important to survival. What happens with trauma is that this filtering mechanism gets kinda broken and the subconscious will let through elements that it normally wouldn't.
The body is very attuned to survival, so things that have nothing to do with it have a cost but do nothing to help that survival. for example, if you take your TV remote and push a button, it flashes light at the TV you can't see. If you look at a rainbow, the color is basically just past red (called near-infared). The TV itself is also designed to exploit the weaknesses in peoples perception of reality to make it cheaper. It reminds me of a youtube video I was watching a while back. It said "why try to make something that can mimic reality when you can make something that mimics the persons *perception* of reality for 1/3 the cost.