Psychedelics make you learn stuff that you cannot easily "unlearn", like any major life experience. It expands your awareness in ways that sometimes are not pleasant (very often, "ignorance is bliss"). That's the reason most psychedelics are not recreational, but rather "spiritual" drugs. They are self-development tools, and like any tool you must know how to use them.

It's totally possible to be enlightened by a bad trip, rather than traumatised. It all depends on your outlook on life, how you instinctively react to adversity. You should see everything under the self-development lens, where everything is an opportunity for growth, and never feel victimised. Your goal after a bad trip should not be just "to recover", but rather to become your best yet. Much like a muscle that grows stronger after you strain it at the gym, psychedelics exercise the mind, and can make you mentally stronger. However, like in the gym, the recovery periods are essential, and over-exercising is detrimental.

In answer to the people who always bring up the subject of psychosis: any extremely stressful event can trigger psychosis in people who are prone to have it (for example a divorce, or any big loss). As a rule of thumb, if you're close to 30 and you've been through tough times and feel fine, you're safe. I personally believe that if you're a lucid, clear minded person, looking for self-development, psychedelics are for you. If you're an easily scared person not interested in self-development, psychedelics are definitely not for you.