When I was really young I got to the point that I could tell when I was dreaming. From that point on I would decide whether or not to continue the dream, normally the continuation would be rare. Then for a few years I rarely had any dreams (at least when I awoke I had no recolection whatsoever). Once I hit mid highschool they returned, but were rarely about me. I also have no control any longer. I once however had a dream (in all seriousness) about a class with a teacher I had the previous year in a different room with different people. I thought that was impossible due to already having him once, but then during my senior year in the middle of class it all flooded back to me when the girl next to me said something. That very seat I sat, that new class room the teacher had recieved through recent construction, and it being the same teacher... it was all the same as the dream.