Many masters teach not to get hands on the scene too much, to capture only instants that are real and often I see pictures being hard criticized because built by the artist or faked. I think that even if I create my own set, everything I see through my lens is real, because my camera cannot take anything which is abstract. As a photographer I really estimate once said: "Photography is the art to make invisible, visible".
Last year I showed a photo which I've made to a teacher of mine. In this picture I've changed the color of the sky from blue to green, nothing special or hard to do. He was like: "No, this sucks... this isn't real!". Why should it not have been? When I took the picture, that sky was there, I've just wanted to change its color as though I saw it in my head. My thought can be unreal, but once I'm able to put them inside the image, they become part of it and part of reality, my reality.
This is, instead, a little heart I drew on the window of my car. This is not an event or something real that happened, I decided to create something to shoot at. I love hearts, they make me happy. And I also love the contrast between purple and orange, so I've changed the colors to my favor. Is this picture unreal? Maybe, but when I captured the scene, it was real for sure, because I saw it in front of me, with my eyes.
It is a great rule and also the principle of the photography to portray reality as it shows to us, but as well as the other arts, rules are made to be broken. But this can happen only if the artist knows what he is doing, because otherwise he will only produce chaos.