In college I read a book “The Varieties of Psychedelic Experience”. I was telling a guy I would love to experience all that stuff IF the drugs were safe and no possible brain damage. He had been into drugs for years and cleaned himself up. His dismissal always stayed with me: “Those things are s**t”.
The Doors of Perception by Aldous Huxley does a good job.
All in all, I cannot fathom those who advocated widespead use of such a potent drug.
Unless set, setting and company is controlled, one can have a disastrous experience. Dropping acid at school or college on a whim is what often led to a horrible experience.