Back when I was in my late teens, and early twenties, I seemed to be a phenomenally good Tarot reader. I did readings for some friends that were in the Air Wing. When we got back to port, they went to their bases, and we didn't see each other until the next major cruise, when they were aboard again. Two of them looked me up and told me about how I had hit it on the mark, and had been so accurate etc. At first I was flattered, and a little full of myself, then it dawned on me, what if instead of predicting what was to be, I had, through my readings caused them to make decisions that made the outcome match up with the readings. That possibility causes me nightmares to this day.