Humans live in the past. We often replay good and bad memories over and over again in our heads. And let me be clear: this "replaying" of memories is both voluntary and involuntary.
Most of us run across our experiences from the past in our dreams. And we don't just relive our past experiences--we manipulate them.
In our dreams, we see the past. We look forward to the future. We interface with people who we care about. We interface with people we've never met. We see ourselves walking down that one road.
I've only ever been able to lucid dream a few times in my life. As many of you know, lucid dreaming refers to you taking complete control of your dream. It's meta in that you acknowledge that you're dreaming without fully waking up.
It's actually kind of funny when it happens. I can remember talking to others in my dreams and saying something like "But, it doesn't matter because this is just a dream." It's hard to remember what I did, but from experience, they rarely ever turn into nightmares.
This is the thing that most people aren't aware of if they've never experienced it. It used to happen to me all the time. I mean, waking up and not being able to move your body is a pretty scary concept, especially for the first time.
Believe it or not, but this is the origin of the "nightmare." And I can see why. Lying in bed and seeing the room in which you are in. And all of a sudden you hear strange noises. For example, I remember hearing stomping from the hallway. And all of a sudden, you feel this presence leaning over you. It's like a shadowy figure. Sometimes, you believe it to be someone you know.
Some people have claimed that this is some demon or dead person visting you. In some accounts, people claim that this "figure" hurts them. This has never happened to me. Probably similar to when someone hurts you in a normal dream and you wake up in pain.
And, just in-case this ever happens to you, just remain calm. Try to move your fingers and you'll eventually get out of it.
So what do our dreams mean? I'm sure there are many theories out there. However, I'll only offer mine.
Our dreams are merely a reflection of ourselves. They tell us who we are, how we feel, and who we want to be.
They reveal to us our internal fears. They prepare us for the future. They motivate us. They are vices that let us know what we're nostalgic about. They tell us who we miss.
I could probably could go on and on, but I'll leave it at that.