As a postmodern person - I see a clear message in that work of art, a theme I might used before but this picture screams it:

Different people are facing the same experiences, they might be in the same place, opening the same door and entering the same place, yet - one of them sees this act as a waste of time, just like moving though a door to the same exact dark street, yet the other sees the door as a magical object, full of lights - a door that when he will pass though he'll look at the same place, the same street - but now the whole street is full of magical like lights, there is a magical tree you can enter into and create your own place, no wonder kids love playing and hiding inside - they have the power to imagine while most of the adults pretty lost it.

this is a metaphor for the way people look at life - one person can look at his life and think that they are boring, that he doesn't like his situation, that he wish it was different. The other might have pretty much the same life, but he has an open mind - he just LOOKS DIFFERENTLY on the world, he sees his life in a positive perspective, finds the good things and enjoys his life without thinking "what if" - he has this particular life, and he accept it and submerge himself in it - finding magic, colors and light in the everyday life - just like passing the door to the same street, but seeing it full of light and magic.

Thanks for the post velimir :)