The Past- Beastly or Beautiful?

It is a sit-in-the-shower-and-think type of night. I often get in these moods where being reminiscent is the only emotion I can seem to manage. I sit in the shower and stare at the droplets of water spattering the shower lining. I can see the Picasso-like pattern of the curtain behind it, blurred through the drops of liquid. I stare and stare, thinking about things past, things that should no longer matter, guiltily sighing as I realize my skin is bright red from sitting too long under the burning shower head. 
I often wonder why I do it to myself- bringing back events I can't change, remaking someone into a person that he or she will never be. It does no good and only puts me in a foul mood for days, muddying up my dreams with images I continually seek to destroy in real life. I wander between dreaming and waking, hoping the images come to life, wishing the past did not turn out the way it had, remaking decisions that have been set in stone years ago. 
It is a sickness, a disease of over-emotion, yet I go through periods where all I can do is live in the past. In my lucid moments, I remind myself that if things had worked out the way I see them in my head, then I would not be sitting in my car staring at the dashboard daydreaming or scalding myself on the floor of my shower. Why do we do that? Why do we think we can change people or events? Why do we think we can mold our own lives and the lives of others? 
We really only have so much control, and that control only extends to our own actions. Often I think I can control the outcome of a situation, when in reality I can not because I have learned that people are unpredictable. You can not change the will of another, you have no right to take that freedom away even if it benefits you. 
Now I realize this post is semi-cryptic, but when people from my past pop up in dreams or real life, it often sets a chain of events in motion in my mind. I get stuck in this bubble where I think I could be living differently now, when in fact, everything does happen for a reason. Everything happens because people decided it would. Two people decided an outcome. Two people made choices. Both parties now live with those choices. 
The past is not a force you can change; it is not a force with which you reckon. It is certainly not a force to get caught up in as I am now. I hope that writing my thoughts down will allow me to verbally relieve myself of the tension I have created in my mind. The past can be beautiful or beastly if you allow it; it is one lover from whom you never quite recover.