There was a time when the imagination was viewed as something to be avoided. Rationalists reigned with a viewpoint that said facts and just the facts led to a healthy and intelligent adult.
Boy - were they wrong! It turned out that people (especially children) need imagination and play to develop in healthy and well-balanced ways. Such activities inform emotional, social, and physical development. Think about your storytelling and find ways of celebrating the imagination! After all, even a scientist needed a moment of "what if.....?" as they explored some new theory or invention. See a great site devoted to children and the imagination at http://www.wholefamily.com/aboutyourkids/columns/ruth_3/imagination.html