Why Do People Have Dreams ?

According to Psychiatrists , Our Mind is divided into three parts as unconscious,sub-conscious and unconscious part. The Unconscious part is the storehouse of all our knowledge,skills,dreams,desires and expectation. These all desires and expressions keep trying come to the conscious part of the mind but they are controlled by the sub-conscious part and only such expression come to the conscious part that is required or expressable in the society. When People are sleeping,the sub-conscious part of the mind becomes inactive as a result the desire and expressions from the unconscious part come to conscious part and we have dreams.The stronger and unexpressed desire are more often they come to the conscious part. This is the reason why People have Dreams.