I used to be this way, but found that after 2 decades of "curious exploration", that there was something deep inside the trip that was upset or angry with me. Often sending me into fits of paranoid delusion. It was almost as if the spirit of the molecules had gotten together and decided that they were tired of me taking and not giving. Not bringing anything to the proverbial table.
Clearly, I am not making any sort of assumption as to your intentions, whether conscious or subconscious. I can only speak as to my experiences. I hit point to where no matter what I took, I would get into this looped thoughts of a disgust that I could feel in the ether, directed towards me. When I stopped taking these compounds simply with the intentions of getting "messed up", I began to learn from them again. To have positive experiences.
I believe that the spirits of these compounds have emotions. Emotions that can go in many different directions. Many more than we have words or explanations for. I also believe that much of what we experience is very internal, and perhaps my discomfort in myself played a part here? But in the end, adding the intentions, and making sure that I was bringing something into the ether remedied my issues.
That being said, there were 20 years of not setting any intentions that worked wonderfully. There just seemed to be a wall I hit after a certain bit. Also there were a few really heavy shared experiences that left me questioning the very fabrics of our reality.
I guess what I am trying to say is that, while not necessary, setting an intentions helps you get on the level in which you want to be before the unpredictable nature of the compound takes over. Almost like buying the ticket to your destination, and getting on the train. You trust that the train will take you to where you want to go, and that you will have no issues getting there. If that makes any sense

sometimes I have difficulty explaining my thoughts.