Hypnotism is just a condition of relaxed focus. It's a normal state. Actually, each and every one of us enters such a state - occasionally called a trance state - at least twice a day: once when we are falling asleep, and once if we wish waking up. Such significant of fuzzy, timeless state between dreaming and awake is a trance state. Whenever a nine-minute snooze-button seems to provide you lots of time to have an-hour long dream, that's a trance state.
There are lots of other times that individuals enter a natural condition of trance. Driving, watching TV, listening to music, working on a favorite hobby or activity in the "flow" state. These are all "altered states of consciousness," and all are various levels of trance. Trance is normal, natural and common.
Many people leave their first hypnotherapy session saying, "I wasn't hypnotized - I knew what was going on the whole time!" Well of course you did! Hypnotism is not a state of amnesia or of no awareness. Just the opposite true, in fact: hypnotism is a state of very heightened awareness and focus.
Bolywood/ Hollywood has perpetrated a lot of misconceptions about hypnotism, and not remembering anything from the hypnotism session is one of those myths. Only under particular situation would an individual forget all aspects a session.
A lot more can be done when the person undergoing hypnotism remembers everything.