Hypnosis works. I know people who are qualified to do hypnosis, and I have been hypnotised myself... heck I could in theory hypnotise people. It's just a little dangerous thats all.
I honestly can't believe people 'don't belive in it'. There are many documented cases of it working, and it is used all the time. It's proper science. It's like saying "I don't believe in Newtons laws of physics."
Major point here, Hypnosis works on the power of suggestion on the unconscious mind... So in a nut shell, if you don't want to be hypnotised, you can't. If you don't follow the Hypnotists instructions, you can't be hypnotised... There is also a percentage of people who can't be hypnotised for some reason or another.
Another point... DO SOME RESEARCH! RESEACH CHH CH- ALL GLORY TO THE HYPNOTOAD!
http://en.wikipedia.org/wiki/Hypnosis