This is because it is not nearly as weird of a state as we think it will be. Some deep trance states can produce some unusual feelings and visions, but there is always a part of you that knows you are acutally right there in the chair, in the office, and safe. Regression to childhood events is, in my opinion, one of the most effective methods of Hypnotherapy. Ask your subconscious to take you to the cause of the problem and it will take you into a memory or event that created a conflict, negative decision or a negative beleif about yourself. These decisions and beliefs determine our behavior and reactions to our present circumstances.
Memories get mixed up some times in our brains storage system.
Some memories are remembered with the details a little skewed. However, this does not mean that the feeling behind the memories are not valid. In regression therapy the trapped emotion is the goal. Just because the details are a little off, does not invalidate the emotional reality that is the cause of the problem. So, we release the emotinal block and transform the memory into a memory that now operates on the positive lessons and learnings that were there.