While I would agree that most dreams are not real, and are reflecting something in the subconscious mind, I do think there are rare instances where something else occurs--it's like having a third party hack into the communication between brain and spirit, for lack of better words. This can occur if another spirit--this can be God, or also the spirits of the dead--makes a direct connection with you.
In one case I started out fully awake, felt the intrusion onto my consciousness (mind you, not a threatening one), and felt myself slide into unconsciousness, taking very rational notes on the whole process...what it felt like, what I perceived, and what I felt emotionally--everything. I did not will this to happen, but I also didn't resist it because I understood what was happening to me and that the only way to learn what I was supposed to was to comply with it. As you can see, I'm still here, and in sound mind and body today, so I made the right choice. 
These are VERY rare, though. I DO NOT have them often, by any means.
