The Skin Horse (taken from "The Velveteen Rabbit")

The Skin Horse had lived longer in the nursery then any of the others. He was so old that his brown coat was bald in patches and showed the seams underneath, and most of the hairs of his tail had been pulled out to string bead necklaces.  He was wise, for he had seen a long succession of mechanical toys arrive to boast and swagger, and by-and-by break their mainsprings and pass away, and he knew that they were only toys, and would never turn into anything else.  For nursery magic is very strange and wonderful, and only those playthings that are old and wise and experienced like the Skin Horse understand all about it.
"What is REAL?" asked the Rabbit one day, when they were lying side by side near the nursery fender, before Nana came to tidy the room.  "Does it mean having things that buzz inside you and a stick-out handle?"
"Real isn't how you are made," said the Skin Horse.  "It is a thing that happens to you.  When a child loves you for a very long time, not just to play with, but REALLY loves you, then you become real."
"Does it hurt?" asked the Rabbit.
"Sometimes," said the Skin Horse, for he was always truthful.  "When you are Real you don't mind being hurt."
"Does it happen all at once, like being wound up," he asked, "or bit by bit?"
"It doesn't happen all at once," said the Skin Horse.  "You become.  It takes a long time.  That is why it doesn't often happen to people who break easily, or have sharp edges, or who have to be carefully kept.  Generally, by the time you are Real, most of your hair has been loved off, and your eyes drop out and you get loose in the joints and very shabby.  But these things don't matter at all, because once you are real you can't be ugly, except to people who don't understand."