What do you think about hypnosis?

Hypnosis is a wakeful state of focused attention, you can't use it to make anyone do something that they wouldn't otherwise do. I personally think that people who say that hypnosis helped them stop smoking or overeating and things like that are probably helped more by their own belief that it will work and their altered expectations. I'm pretty sure that if you are certain that it won't work then it probably doesn't.