I have a lot of thoughts, recently.
I made a post a bit ago about "all religions are right," where I basically say there's something to people experiencing something real that can't be explained which have resulted in different belief systems throughout the world. I use quantum physics as a catch-all explanation, but the 'why' isn't important. I think that we get to "higher states" of conciousness, and that it is correlated with certain parts of our brain being active and it affects our perception of time and maybe space.
My basic theory would be that something like an intense focus on music, or composition of such, hitting emotions we can't typically hit, would be one such instance.
When major events happen and things seem to slow down would be another example.
Meditation in many forms helps move towards this.
Higher than these would be dreams, particularly vivid and lucid dreaming, which I've been pushing myself towards to explore this.
Possibly the highest that we have a good example of are NDEs.
So I think NDEs are a rare instance where we are able to experience that greater element of life that we can't quite define. Frequency, vibration, and energy as Tesla posited. Lots of people have their explanations for what it is: demons, angels, spirit energy, ghosts, akashic suchandsuch, alternate universes, astral suchandsuch. I think they're all right and wrong in ways, but I think NDEs are the clearest glimpse we get into whatever that is.