A Dream is a series of emotions, images and sensations that happen when we sleep without our control. There are about six persistent theories on why we dream, which are follows:

1). It is the integration of our experiences and what we have passed through the day or seen during the day experiences. It's believed that we have seen during the day, is often repeated when we sleep.

2). Emotions. Dreams are also tied to how we feel and moods, this can be expressed through nightmares.

3). Opposite of our emotions. There are those who teach that our dreams are normally not connected to our emotions, and they happen to lift our spirits when we feel low or had a bad day.

4). Completely Random impulses that happen when we sleep and may not make any sense.

5). Memory reboot. There are those who believe that dreams are connected to the brains' investigation of the things that happened during the day.

6). Freudian  dreams. Freud talked much about dreams which to him, they are representation of unconscious  desires, thoughts, motivations and wish fulfillment. Sigmund Freud  believed that dreams has connection with imaginative thinking, and you can interpret them to give you the real meaning.