We are all in dream state,
one is not knowing is a dream – Night
another is knowing it is not a dream – Day
First one,
We need sleep to rest the body but we all know our mind never sleeps. the mind rearranges our memory in the deep sleep state. The arrangement may look real but all understanding in the dream was more like a metaphor. There is no conscious mind in the dream all you recollect in dreams are all from the subconscious. You cannot read and write in a dream because it all belongs to the conscious mind.
The dream always looks real because you live in a parallel world inside of you and it will teach you or advise you in the metaphor form. The dream can be understood directly; it has to be interpreted through its metaphor. Hence there is a study in which you can reach a near understanding of your dream incident.
Second one
You are conscious but it is still a dream in waking. You never agree you are in a dream state coz of your consciousness. It is just upside of the night dream. In night dreams you live on subconsciously and in the waking state of dream you live on consciously.
Both try to interpret with one another.
The waking state interprets the sleep state metaphor and sleep state interpret the waking state of dream.
Both are dreams only
If you understand, you can travel from day life to dream life and vice versa.
Your understanding of both states will bring you great success. First one will give you a metaphorical way of finding the solution in a waking state. The waking state tries to execute and sends the message to the subconscious to check whether what you did in the waking state are correct, and request to help you in the dream in the form of metaphor where you will interpret as soon as you get up and correct yourself on moving day state.