Dreams?

So my sleep has been riddled with crazy dreams lately...  people from my past have made guest appearances in my dreams and have made me wonder why they are showing up when they obviously aren't part of the show anymore.  This has made me wonder what dreams are all about.  Are they really our subconscious speaking to us through visuals in our sleep?  Are they messages from beyond that you are receiving? or is it just your brain downloading thoughts and events from the day and they really don't mean anything at all?

I'm not going to get into any of my dreams, because the last thing I need is other people analyzing my craziness!  I will give you my opinion of what dreams are though - as I am hoping you tell me yours in return.

I believe that dreams are the door to our innerself.  As our brain is creating a data dump from the day's processing, your subconscious is finding a way to file all of the information into cabinets for later reference.  I think that as this data dump happens, you are given answers to questions and problems that you may have been facing in recent awake hours.  I also believe that people that have passed are able to visit you in your deepest sleep.  Yes, this is getting a little "out there".....  but this is what got me thinking this.

Back in highschool, a very close friend of mine was killed in a car accident.  I was able to attend the wake, but not the funeral and I had always felt guilty for this.  I was also very concerned about the way he died; did he suffer at all, was it an immediate death, etc.  A few days after his funeral, Tom appeared in my dream and answered all of my questions.  I confirmed the information with his sister and it turns out that everything I had "dreamt" was true.  Believe it.....  or not.  This is not the only story that I have regarding death and dreams either. 

So.. tell me....  what do you think dreams are?