Dreaming is a continuance of our daily mental processing and consciousness. You might say it's the restful stage, as we have less outside influences stimulating our responses. So we are free to explore, learn and potentially process unfinished "conscious" ideas, while in our dream state. So free, we may not feel in control of what is taking place.
Some may only focus on "dreams" they remember or those that present the most extreme impressions, while there is so much more occurring within our resting-consciousness. These are things sleep/dream experts strive to discover.
It may be that dreaming is our evolutionary attempt at expanding the use of our brain and mental synopsises, as we are reminded we use a very small portion of "brain power", or even have conscious access to it.Connecting-to-the-Value-of-Why 2005-2008 ©