Have you ever been hypnotized (by a professional)? If so, how did it work for you and why did you do it?

I attended a Magic and Hypnotism show when I was in high school. I was chosen among 18 other people to go on stage and get "hypnotized" you have to really be able to concentrate hard enough, and have no reserves at all about it working. It didn't work for me in the slightest, and I knew it wouldn't before I went up there. But I swear to you my friend was. He was a very shy guy and the hypnotizer had him do an Elvis impression in front of EVERYONE. I know that he would NEVER NEVER do this in real life...so I really do believe he was.