Dreams are funny things. They contain seemingly random people and events that make absolutely no sense (and quite often openly flout the laws of nature). They leave us confused and asking how we came up with such strange thoughts in our sleep. Why do we have dreams and why are they important? Dreams are our sleeptime connection to God/Source.
Even though we don't always understand dreams, they are very important to the human psyche. People who don't go through regular sleep/dream cycles begin to have mental breakdowns. Dreams are our subconscious way of working through issues and problems that occur in our daily lives. Quite often we receive insights at some level. In our sleep we are not burdened by the confines of our day to day world so our hearts are more free to explore the unlimited knowledge that is Oneness.
There are times when we have dreams we just "know" are prophetic. Typically, these dreams are knowledge that is so important for us to have they come through in our sleep. If you are awake and aware in other ways, these sorts of dreams will back up what your conscious heart connection is already telling you.
Understand that dreams are there to make sure all of us have some connection to God/Source, whether we consciously seek it or not. Pay attention to those dreams you remember. Chances are they will reveal information that could change your life!