Although, I've tripped many times, I've only hallucinated twice in my life.
First, when I was little, I was really sick, and counldn't keep anything down, I was prescribed Compozine. I went to sleep that night and woke up and nobody was there and all I could see were "Chrismas lights". I kept screaming but nobody ever came. Yea! that was soooo coool...not.
Second time was caused by amphetamine psychosis. Don't take nine white crosses at once (in the day when white crosses were not bunk). I thought the cops were outside my basement bedroom window and I could see their infrared camera in the shadows. Yell'd at them, and all the while my parents were asleep upstairs. I'm so glad they did not wake up.
Bottom line is when you are truely hallucinating you don't realize it. You're caught in that moment of reality. How is this recreational or mind expanding.
On the other hand when doing high dose phsychedelics, the Open Eye Visual's (OEV's) can just be so thick that it's hard to recognize your physical surrounding. Your brain neurons are firing all over the place, your visual processing is trying to do what is does and organize it into known templates. Thus, you get all theses physical objects doing impossible things like melting, morphing, and intense brightly colored geometric patterns. I've had it so bad that I had to reset my visual field by turning the light off. Then, when the "lights off" visuals filled up my visual field, turn the light on, repeat rinse.
What I think alot of people think may be hallicinations are really lucid dreams. It's like a mental impression that manifests itself into your visual thinking, but you did not get the info for the vision with your normal visual portal. Now that made sense. This is all just words.
After looking up the term in wiki, I guess I'm being anal.
Damn, I've hallucinated bunches.
So yea, take more.