Funny story I like to tell about self-hypnosis. I feel it really worked for me! When I was in High School, I was lucky enough to take a seminar led by the parent of one of the students, who was on the board at the Carl Jung Foundation in NYC . He taught us all sorts of cool things, like synchronicity, about the I Ching, and yes, how to hypnotize ourselves.
I put the latter to good use during college when I was taking economics, which was a real stretch for me 'cause I'm more of a artsy creative type, but I was also very curious. Well, I worked really hard. Come time for the Final Exam tho, I totally blanked out on a certain graph. I KNEW I had studied it, but what was on it? I felt safe enough to put myself into a trance (who was going to talk to me in the middle of a huge lecture hall? You coulda heard a pin drop), I went back in time, looked at the graph again, saw all the detail, brought myself out of the trance, answered the question, and got an A in the course. That meant a lot to me, too, because it was the only A I got that term
A few other times I've experimented with going back in time (one time I re-listened to the incredible mundane conversation at the table behind me, so not worth the trip
) but have yet to harness it to any great end such as weight loss etc.