QOTD #6 - On perpetual childhood

"When I became a man, I put away childish things, including the fear of childishness and the desire to be very grown up."
C. S. Lewis

Your turn: I've never understood why children seem to lose that sense of wide-eyed curiosity and goodness when they become adults. For too many of us, life seems to beat it out of us, and I'm not entirely sure why. Do we really need to "grow up"?