Imaginary play and thinking outside the box are essential elements to successful child development and learning. They are also, of course, much sought after skills in business and art etc. the importance of critical thinking comes into play in examples like kids jumping off roofs, imagining they can fly by holding the corners of a bedsheet. or not wasting the company's time and money (or your life) on scientifically impossible endeavors. dreaming about building a bridge or curing cancer is wonderful. but eventually you have to stop just dreaming and prove the idea works.