C. S. Lewis, Weight of Glory
Perhaps ‘nostalgia’ is meant not so much to be a fantasy as a sign of a reality more real than the objects within my grasp. Perhaps it is not so much a sleep-inducing past memory as it is a life-giving future hope, a future reality that invades our present, asking not so much to be a temporary escape as to be a permanent source of strength and courage by which we engage with the reality in which we now live.
This is not an invitation to immerse ourselves in nostalgia, but to take its cue by paying attention to the longing for something more, something grand, something utterly and excruciatingly fantastic.
(If you have never read Lewis' sermon entitled "Weight of Glory," it's a must read!)