Sunsets are loved because they vanish.

Flowers are loved because they go.

The dogs of the field and the cats of the kitchen are loved because soon they must depart.

These are not the sole reasons, but at the heart of morning welcomes and afternoon laughters is the promise of farewell. In the gray muzzle of an old dog we see goodbye. In the tired face of an old friend we read long journeys beyond returns.

– Ray Bradbury, From the Dust Returned