When, if not childhood, is the best time to have dreams? When you are a child you can be anything from royalty to a fireman to a professional butterfly catcher. This is the perfect time to start down the path of what one wants to be.
Of course, not everyone is going to become what they want to become, but why make children face that hard reality when they are still figuring out how to tie their shoes? I absolutely believe we need to help set kids future expectations. Maybe we can help set those expectations in reality as the child ages, but childhood is magical and it is when you need to cultivate dreams.