Probably the only valid insight I gained from all the drugs I took over the years was: It gave me some understanding of the concept of “multiple realities.”
By that I mean, when I was tripping on acid, “reality” would look one way. When I was snorting meth it would look another way. When I was getting drunk it would look another way. When I was smoking pot it would look another way. And even when I was sober my “reality” was constantly shifting. Depending on my emotional moods and chemical balances and so forth.
So when I saw some “crazy” person acting weird. It gave me a perspective. There was a certain “logic” to their behavior that made perfect sense to their particular mind and their particular mental state. Or when I saw someone who had a completely different opinion than me about what “reality” was, it gave me a certain perspective. About their biases. As well as my own biases. We all create our own “realities” to a large degree.
It was one of the things I realized vividly the first time I took acid at age 17. I realized that the “outer world” was also a construct of my “inner mind.” And that we create our own realities to a large degree depending on the biases and inclinations and chemical state of our own minds.
I think it was a similar understanding to the Zen and Taoist notion: “If a tree falls in the woods and no one is there to hear it, does it make a sound??” Because the reverberation in your ear drum “creates” the sound just as much as the falling tree does.