Does hypnosis really work?

I was watching a video last night that had the colourful swirl thing that you had to stare at and this woman was talking in the background. She would say to close and open your eyes and feel you muscles relaxing and all that. At the end of it, I thought i was hypnotized because it was like reality hit me at the moment and I was like "Oh, I'm in my room again." I was weird. Was it actually me being hypnotized or was my brain tricking me to thinking it? Also, why do hypnotists almost always use spirals for hypnosis?