Story,Cinema & Sex

Ok, Sex was for attention. I want to write some story. I am not clear about content, size or anything. I want to make a film. Again I lack clarity. I know what I don't want. I don't want artificial drama. I feel all literature, movies are works of fantasy. OH. One fundamental question is why do we need literature and cinema or for that matter any other art?
I am not confident that, I will be able to find an answer for that.
Coming back to my story, I have lot of material, just don't know the correct recipe. I have such fundamental questions like "does story need to have a structure, a purpose, a theme..?"
I should not allow all these questions from attepting something. So I will start writing something today and hopefully be done with that in few days. Most probably I will hate what I have written very soon. But then, I want to take snapshots of my stupidity. Without a reason, as usually, ofcourse.:)