Mary Poppins and the Dancing Cow

I went to the movie Saving Mr. Banks a few weeks ago. I really enjoyed the movie and it inspired me to go back and re-read the Mary Poppins story.  I remember enjoying the book as a girl and was curious to see again how the book differed from the Disney movie....turns out it is pretty different.

But, here is one story from the book that never made it to the movie. I've been trying to decide if I think it is an optimistic or pessimistic story.  It is from the chapter, "The Dancing Cow," and goes something like this.
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The children see a cow walking down the road and ask Mary Poppins about this unusual sight.  She remarks that she knows this cow well, she was a friend of Mary's mother, and goes on to tell the children about the cow.  This cow lived in a beautiful meadow filled with buttercups. She had everything she needed and was quite content and happy with her life.  One evening, as she was getting ready to go to sleep, she had this urge to start dancing.  She hopped up, skipped around the meadow and danced all night under the stars. When the morning came, she was still dancing.  She felt light and filled with joy, but as the day went on she couldn't stop dancing.  All day and all night, day after day, she danced in the meadow. She couldn't stop to eat or sleep and after a week was worried that she may never stop dancing.

She set off to seek the advice of the king, who was a wise man.  After some deliberation, he noticed that the cow had a star stuck on her horn and that was the cause of her dancing.  The king's courtiers tried to remove the star, but it was firmly stuck.  As a last resort, the king suggested that the cow try jumping over the moon.  The cow wasn't too keen on this idea, but they went out to the courtyard and she leapt into the air.  She sailed up, high in the sky, and soared over the moon.  As she passed over the moon she felt the star fall away and return to the sky.  She came back to the ground in her old meadow and her life returned to "normal."  No dancing.  She was happy to return to her life of order and calm.

But, after some days she grew dissatisfied. She missed her dancing. She missed the joy of skipping through the meadow.  She visited Mary Poppin's mother and told her story.  Mary's mother replied, "You silly cow.  Stars fall from the sky all the time, but you can't expect two stars to fall in one meadow during your lifetime. If it were me, I'd go look for one. " 

"I will," said the Red Cow joyously, "I will indeed."

At the end of the story, the children look out in the lane but the cow has gone.  "I do hope she finds one," they say quietly.
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Now, my question is:  optimistic or pessimistic story?  Good that the cow can hope to find another star?  Or, sad that she has roamed the streets for years looking?