Hypnosis happens all the time. Every time you watch a commercial and feel the need to actually buy something stop for a moment and ask yourself why, how come 30 seconds ago you never had the same need? When watching a movie ask yourself why is it that your body and emotion react to what you are seeing there as if it were real. In fact, advanced sales people use conversational hypnosis where without trance you actually feel deep need to follow their suggestions. Ever stopped for a moment to ask yourself why? Google it mate. Ever had a phone call, a text, a letter or an email from a girlfriend who after a series of weird, out of character experiences started to blame you for everything and you felt that feeling 'ok that's it' what you maybe didn't realize that knowingly or by accident she just planted a post-hypnotic suggestion into your mind. She decided, for whatever reason, she didn't want to go any further with that relationship and now just programmed your mind to make a clean cut in confidence you would never come back. Heck it has been used by Holliwood so much that one would think people would already take a notice, but apparently not. (Does "how to lose a guy in 10 days" ring a bell? lol, or take any other similar movie http://www.youtube.com/watch?v=vVns_QUtTxA)
And now you are protesting you were never hypnotised. Actually you were. You took up the story somebody else created for you, you ran with it as if it was reality and the funny thing about our mind is that we often can't distinquish reality from misdirection of someone playing on biases, and stereotypes that are ALREADY ESTUBLISHED in our minds, already planted shell we say. In fact to top it all off, wtbs theocratic school teaches conversational hypnosis methods all the time. Heck, it took researching advanced Ninpo material and lots of observing to actually realize what had been used on me. What do you think avarage Joe or Jill know when they've been swept by hypnotic methods? It hardly gets noticed, in fact unless they had specialized training in related field most will say what they saw was absolute reality and it was their own will that made decison (yeah right), becaused it tickled something profound in us, our sub-conscious underpinnings.
But don't worry about therapy, all hypnosis does is reaching into your sub-conscious. If done by a doctor it will only reveal what's already there without planting anything. If want to know more at least read something form either Milton Erickson or maybe something from Stanislav Graf e.g psychology of the future. It just might reveal something very profound and also stop you from making bad decisions in future ;)