A cheeky four-liner imagining the day a child gets to be grown-up, proud, and finally in charge of their own toys. Its dry little joke of an ending tends to make grown-ups smile more than children.
From A Child's Garden of Verses. See the whole collection.
When I am grown to man's estate
I shall be very proud and great,
And tell the other girls and boys
Not to meddle with my toys.
Public domain. Text from A Child's Garden of Verses (Robert Louis Stevenson, 1885), via Project Gutenberg. View the source edition