Time is the continuous loop, the snakeskin with scales endlessly overlapping without beginning or end, or time is an ascending spiral if you will, like a child's toy Slinky. Of course we have no idea which arc on the loop is our time, let alone
where the loop itself is, so to speak, or down whose lofty flight of stairs the Slinky so uncannily walks.
Annie Dillard. Pilgrim at Tinker Creek, 77.
nostalgia is a natural response to uncertainty and dissatisfaction. At its root, the word breaks down into the Greek nostos (“return home”) and algos (“pain”).