They can produce certain "states" relating to "angelic" or "oneness" as you mentioned yourself, but for the most part these states can be very deceiving and lead one astray on the path to truly know oneself and seek truth within and without.
The excerpt above is very true although when it was told to me I didn't really believe it. Well, I didn't believe it at all! My spiritual experience had nothing to do with a vulgar neurochemically-induced illusion. How dare they talk about things they don't even know!
I can relate to you because, at the time, I was in a similar situation. For years I had been practicing Tai Chi, Chi Cong, Neu Cong, meditation... several hours every single day. I had a "master" that I respected and liked very much. He liked me too.
I was experiencing a lot of "great" and "supernatural" things. The whole nine yards actually : permanent flow in the higher chakras, out-of-the-body experiences, time suspension, dreaming à la Castaneda, meditation lights, "transcendental states", even very audible chi discharges (I have witnesses!)
As Laura said this is a drug. But unlike other drugs it is not labeled as a drug. It is labeled as good. Internal martial arts are considered as a path to spirituality, self-mastery, enlightenment, good for the health, good for the mind, good to face your fear, good to master your body. What wouldn't you use and abuse something that is, according to every available source, good for your and for the humanity?
And unlike other drugs it makes you feel very SPECIAL. Heck, how many people can claim they experienced what I experienced? How many people have gone through those hallmarks of spirituality? Who can be aware in his dreams and direct them? Who can choose his dreams? Who can "activate" his higher chakras? Who can direct audible "chi" bursts? Who can see the light? Who can be the light? Who can feel this warm and sweet energy running through the whole body?
And there is also the investment factor... When you look back at those thousands of hours of meditation, training and sweat, the status you gained in your school, the esteem of your master, the respect of your students. All the sacrifices you made to be where you are now.
There might be also a nagging feeling (not necessarily conscious) that maybe you're somehow wrong. In my case I managed to avoid any conflictual ideas with a handy little narrative : what I was learning in this forum and what I did in my school was very similar. Actually it was even better than that, it was complementary.
Problem is that I had to shove more and more piece of data under the rug to maintain the illusion that I was walking the great spiritual path.
I think the question that exercised me the most and helped me open the eyes about this whole thing was: "Did those years of practice, make you a better individual?". I guess at the time I smiled and gave some kind of smartass answer but the question haunted me and the more I though about it, the more I was discovering not-so-convenient answers...
Some members of this forum were the first ones to give not-so-enthusiastic feedbacks about my great spiritual activities. Up to this point all my friends, my relatives, my workmates were oh-so impressed with my self-displine, dedication, investment in high oriental spiritual and martial techniques. I was becoming almost holy, a kind of semi-buddha, dispensing some wise advises to a few elects. That was a feeding frenzy, my self-importance was pumped to the max (while I was pretending to follow the way of humility!)
One thing I had difficulties to reconcile though was the allegedly high level of spiritual achievement of my master (and of his master) and some surprising ignorance they displayed sometimes. Of course the narrative is that they don't have to bother with material or intellectual things since they've already managed the spiritual ones. Anyhow I was puzzled with this kind of indifference with what happens on Earth, people suffering, unjustice. Although the narratives maintained by me and by them was that they worked hard to help others but on a spiritual level. You couldn't see it but it was much more efficient than any effort made at the low tangibles levels!
Well, in the 4th way teaching, the first step is to viscerally realize that we are just reaction machines, total slaves of our conditioning, beliefs and blindness. That's quite a painful step, it's even more painful when you considered yourself as well advanced on the path to spirituality.