It amazes me to watch little kids play, especially with each other. They hold tiny toys or dolls in their hands and create whole environments, situations and story lines for their characters. It's not uncommon to hear a child say "let's pretend" and go on to explain what the next turn of events should be in their make believe world.
As we grow older, most of us lose that wide-eyed, creative wonder of childhood. How many CEOs to you hear saying "let's pretend." Of course, they could never say that, for they live in the real world. But, I like to think that designers and creative-types, we haven't lost that wonder. There's something about sitting there and looking at raw materials and seeing what's going to be the next step in the story of that material. In essence, we like to sit and say, whether to ourselves or others "let's pretend" and explore this new world we can create.