“Childhood is the world of miracle or of magic: it is as if creation rose luminously out of the night, all new and fresh and astonishing. Childhood is over the moment things are no longer astonishing. When the world gives you a feeling of 'deja vu' when you are used to existence, you become an adult.”
The idea behind the quotation
Childhood feels magical because the world seems new and surprising; adulthood begins when we become so familiar with life that little astonishes us.