Because you're incorrect. Some people face serious side effects. It can trigger mental illness in those that have a predisposition. It can cause HPPD. Here's a

Because you're incorrect. Some people face serious side effects. It can trigger mental illness in those that have a predisposition. It can cause HPPD. Here's a report I just dug up for an earlier comment: >These symptoms persisted for the last 13 years, with little change in intensity and frequency. All efforts at treatment, psychopharmacological as well as psychotherapeutic, failed to alleviate the symptoms. Often the patient was unable to focus properly with her eyes and tired rapidly while performing intense visual tasks – these deficiencies being detrimental to her studies and professional work as an architect. As a consequence, the patient became depressed with latent suicidal impulses. She also found it increasingly difficult to distinguish between ‘normal’ and ‘ abnormal’ perceptions. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736944/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736944/