Most healthy humans day dream and we all are familiar with the feeling of daydreaming. The easiest way to explain daydreaming is that it's an altered state of consciousness where a person is able to switch off and become less aware of what is happening around them. In that moment they switch off from many conscious tasks and can drift away and explore their thoughts and memories.
This usually happens at a time where a person is an environment that is familiar, safe, comfortable and relaxing. As an example; there are many people that have experienced the feeling where you'll be sitting in class listening to the teacher and before you know it your thoughts wander and you can imagine different scenarios clearly in your mind. Perhaps even considering past memories, playing out past conversations, thinking about what you're going to wear or what you might want to eat later on. This phenomenon is called daydreaming and it's our body's way of switching off, but as soon as something changes in our space while we are daydreaming, we can instantly snap back into reality and be fully aware of everything that's going on around us.
Some aspects of daydreaming are similar to the state of hypnosis, but its evident that hypnosis and daydreaming are definitely very different. There are many differences between them.
The main diferences that come to mind is that daydreaming is a visual switch off, that allows the person daydreaming to explore ideas and thoughts, while they lose concious awareness temporarily about their surroundings.
Its very different for hypnosis, as it's much more focused and goal oriented. Also when a hypnotised person is experiencing hypnotic trance, they can and will still remain completely aware of their surroundings and be aware of everything that is happening to and around them.
As much as a day dream is a state produced by relaxation or tiredness, its very different. It's not a state of deep relaxation that hypnosis creates. Hypnotic relaxation is almost like being asleep while still being able to hear and respond to the environment around you. The level of relaxation during hypnosis is very deep. An hour of hypnosis can feel like hours of deep rest, and it's this therapeutic relaxation that is so beneficial.
Daydreaming very rarely is able to produce lasting change, or impact ones behavour, thoughts or feelings. A skilled hypnotherapist can use hypnotic trance to implement lasting changes for the individual client and help them through effective use of hypnotic trance to make changes in behaviours or feelings, quickly and easily. As an example, helping clients quit smoking, lose weight, reduce stress in their life etc... So as you can see hypnotherapy is goal oriented and effective.
Simply daydreaming of quitting smoking, is extremely unlikely to motivate or help an individual to quit smoking.