I learned how to meditate at a Soto Zen monastery, so just facing the wall. And I experienced the typical sort of makyo (hallucinations) you might expect such a

I learned how to meditate at a Soto Zen monastery, so just facing the wall. And I experienced the typical sort of makyo (hallucinations) you might expect such as faces, a sort of tunnel effect, colours, etc. I recently switched to a Chan method of facing outward and the hallucinations I experienced were extreme. At first, time felt as if it had completely stopped and what felt like days were going by as I sat there, the floor itself became liquid and water droplets were hitting it and I had a number of other pretty intense optical illusions. I was sitting perfectly still and my gaze was also almost still. I meditated for an hour and once it was over it suddenly felt like the entire experience didn't even happen and only a few minutes went by. But I felt amazing after I was finished. Makyo is a common experience, but it was one monks had said to not be concerned with as it's just a hallucination. My experience going through that was ultimately unpleasant and not like the states you mentioned but it was immaterial to meditation itself. I think that part of the purpose of meditation is to recognize a few things, such as your thoughts about the past and thoughts about the future are just like imagination (and a source of strife for people who are caught up in that imaginary world) and your thoughts are things you've consumed, much like your body was once food. So when one meditates you watch these thoughts arise and go by, you feel all sorts of sensations in the body come and go. I don't think the purpose, at least as I understand it, is to experience pleasure or find happiness. I guess if that happens it happens but it doesn't mean anything and is not something you should identify with. I'm no monk so I'm not qualified to teach anything but I think ultimately part of the goal of meditation is to recognize some basic truths about who you are and about the nature of your existence through a careful and very simple method (just sitting), and that's all there is to it.