When I was about 15, I started moving away from the Christian upbringing I had. I saw the hypocrisy of it, and I rebelled. I became angry and my choice at the time was to entirely move away from any concept of spirituality. I became pretty nihilistic, I thought "well then, I guess nothing means anything, it's all a lie". It wasn't a nice place to be, my mom, who is religious (but not in a bad way) was really concerned about me. She didn't need me to be Christian, she just wanted me to have a connection to something bigger than myself.
When I was 18, I ate mushrooms for the first time, it was my first psychedelic. I ate them in a dorm room with a couple of friends and a couple of people I barely knew, one of whom I didn't like very much. I didn't know what to expect. I thought maybe it would be like "super weed"... I thought I'd laugh a lot and see cool shit. Instead, I woke up from a dream, but that dream was my life... I saw my life recede into on blip among an infinite number of similar blips. I realized I was the universe, and that we all are the universe. I felt infinity, I watched the course of the evolution of all life on the planet, and then I zoomed out and saw the scale of the universe, and saw that in the universe was the same as the structure of an atom. It was exactly like how when you wake up and a dream becomes so obviously just a dream, and the greater and more consistent reality of being awake becomes, again, what is so obviously real, like how could I have thought that dream was real? The reality of what I was experiencing was self-evident. The experience was incredibly profound, and it changed my life. It set me on a path of being connected to something much greater than this little life of mine. That is the first and most important way that psychedelics changed my life.
I have had some other +4 experiences, too, that showed me what I feel are truths about existence, but although they're very important to me, nothing can compare to that first experience of blowing the hinges off the doors. But nevertheless, those experiences also helped to shape my understanding of the way things are.
Over time, I realized I didn't need, or want, go keep trying to shatter my ego. From there, I started tripping purposely while putting myself into uncomfortable situations, largely social situations. I got picked on a lot as a kid and it had a profound impact on my self-esteem. Through the purposeful use of psychedelics, I helped myself to overcome that and learn to be more outgoing and confident in myself.
I also did an ibogaine flood dose which brought me out of a 10 year period of intense addiction to opiates, and which changed me in many ways. I came to understand the value of taking care of myself, and I rediscovered music in my life. I healed from an abusive relationship and remembered who I was... I changed my body shape entirely through working out, and redefined my life from a place where I actively wished to die. Although I did relapse eventually when my dad was dying, I still am in a much better place than I was then, and ibogaine is directly to be thanked for that.
I now use psychedelics primarily for recreation, and also to help me to stop and smell the roses, as they say. I use them to help me maintain a connection to my inner child, to stop and spend 5 minutes looking at a leaf or a flower and marveling at the fractal nature of life. I use them to remind me how improbable and amazing it is that we exist at all, and that we live on such a beautiful and verdant planet. I use them to help me achieve a deeper understanding of music and art. I don't think I really NEED them anymore, but they continue to bring me positive results in these things. I would welcome another ego dissolving experience, but I don't seek it.
psychedelics are the one class of drugs I consider to be fully positive in my life, and that I plan to continue to use periodically for the rest of my life. The ways that they have helped me are numerous and important to me.