The word dream stems from

Keep in mind that the word dream stems from the Middle English word dreme, meaning joy and music. . - By BryanJ / Source: The List Universe

The desires only supply the impulse

The desires only supply the impulse. The mind creates the dream out of the materials supplied by the experiences of the waking state. The dream creatures spring up from the bed of Samskaras or impressions in the subconscious mind. Indigestion also causes dream. The Taijasa is the dreamer. It is the waking personality that creates the dream personality. The dream personality exists as the object of the waking personality and is real only as such.Swami Sivananda

We want to forget bad dreams

We want to forget bad dreams as quickly as possible, lest by remembering them through the conscious mind we impress them in the immediate subconscious and make them manifest in daily life. Thinking about a bad dream is to create. Forgetting it is to avoid creating. Therefore, if you have the slightest worry about dreams and are not directly under a guru's guidance on a daily basis, it is best to let them slide by and consider them unimportant and not a part of you, as you would consider a television program to be. - from Satguru Sivaya Subramuniyaswami

Really bad nightmare kinds of dreams

Really bad nightmare kinds of dreams are not natural to the sleeper's mind. Therefore, we must assume that they are produced by outside influences, such as what the neighbors are going through in the next apartment, the apartment above or the apartment below, or what a dear friend or relative may be experiencing in daily life. Subjective as they are, the frustrated, confused, even threatening, dreams of this nature are taken to be one's creation or one's own problem. However, this is more than often not true. A child may be tormented by nightmares and wake up screaming, and the solution would be to have it sleep in another room, away from the next-door apartment where the husband and wife are battling, entertaining hateful thoughts. These kinds of quarrels permeate the inner atmosphere one hundred yards around, as far as the loudest voice could be heard if there were no walls. This is why those on the path seek the quiet of a forest, a life away from the city, in order to perform sadhana in their spiritual pursuit. Dreams of capture and chase are not products of one's own mind. They are definitely outside influences. - from Satguru Sivaya Subramuniyaswami'

Day dreaming seems to be

Daydreaming seems to be the default setting of the human mind and certain brain regions are devoted to it, U.S. researchers have reported accordingly. Some people make it a regular practice. Some others make those dreams come true.