The perfection of personal existence is not found in abstractions, but in concreteness. Our value and dignity don't come from our being instantiations of a type (e.g. "human nature" or "rational animal"), but from our being unique, incommunicable individuals.
The Christmas story is not a charming tale woven to convey timeless ideals. It is an account of real events, involving particular personalities in a given time and place.
In those days Caesar Augustus issued a decree that a census should be taken of the entire Roman world.2 (This was the first census that took place while[a] Quirinius was governor of Syria.)3 And everyone went to their own town to register.
4 So Joseph also went up from the town of Nazareth in Galilee to Judea, to Bethlehem the town of David, because he belonged to the house and line of David.
We experienced this historicity at a new level when we traveled to Israel last February and visited bibical sites: the Mt. of Olives, the tomb of David, the Sea of Galilee, the Jordan River; Nazareth, Cana and Bethlehem; Mt. Tabor, the Dead Sea and the Negev Desert. I found the Wailing Wall of the Temple Mount especially moving. It is what remains of the actual structure where Jesus was "presented" as a baby, where he was "lost" at age 12, where he drove out the money changers, and over which he wept, foreseeing its destruction.
This is inside the Church of the Nativity, where Catholics believe Mary received the message of the angel:
The fulfillment of our lives, too, does not consist in trying to conform to an ideal, but in answering the call of the moment, in our own time and place.