Humans want to know what's real, what's reality, what's true. We have explored the outside world and our inner worlds for millennia, and we seem to still not be sure what is absolutely real. I think the issue might be that what is really real is not something that can be seen or communicated through language at our dualistic level of perception. We have to transcend duality experientially and consciously in order to know the "really real," sometimes called the Nondual, the One, the Real, the Absolute, or God. Perhaps only at that level of consciousness may we come to truly know what is ultimately Real and True.
Mysticism seems to be largely misunderstood. It seems to be either thought of as a kind of ethereal and vague mystery that can never be really known, or as an impractical lofty exercise that can never truly be achieved, at least in this life. For me, it is neither.