I hate to gatekeep here, but I guess I'm going to kind of do it anyway: A lot of people who have taken psychedelic drugs and report a religious experience or an experience where they encountered ultimate reality, are mistaken.
So we get someone who had a moderately intense psychedelic experience for the first time and it overwhelmed them. That person has heard a lot about the mind-expanding properties of psychedelics, and figures "hey, that must really profound. That must have been religious. That must have been a mystical experience."
And they go about their daily life enjoying the totally-real benefits of taking LSD here and there. They feel happy and sociable. They feel more appreciative about their life. Great.
but look....
sometimes... folks who have mystical experiences have a difficult time integrating that experience. They obsess over it. They attempt to repeat it, but fail because they discover that it is not repeatable. They change their priorities in accordance with their new knowledge, to the bafflement of their friends. They find themselves unable to relate to other people because their priorities have become so far-fucking-out. They seek out people who may have experienced something similar by immersing themselves in religious practices, befriending religious teachers, and devouring everything they can get their hands on.
and so on and so forth.
My only point is that psychedelic experiences can seem very important and religious in nature. How genuinely important that experience was tends to be reflected in the person's reaction to it.