Look at them jangling on the ring, five little brass teeth-combs, and understand that not one of them ever actually touches the lock. When you slide a key into a cylinder, the metal surfaces never make contact in the way your fingers report. What stops them is repulsion: the electron clouds of the atoms in the brass and the atoms in the pin tumblers get close enough that their negative charges shove back, hard, through the electromagnetic force.
You have never once touched your own front door. You have hovered a fraction of a nanometer above it, held aloft by the same force that makes lightning, and called that "unlocking."
And the brass itself. Copper and zinc, both of them forged in the collapsing cores of dying stars, flung across the galaxy in a supernova, drifting for billions of years before condensing into the rock that became the ore that became this dumb little jingling thing in your pocket. The worn, shiny spot near the grip, where the ridges have gone smooth?
That is atoms of ancient stardust, a few million at a time, being rubbed off by your thumb and lost to the lining of your coat. You are slowly filing the key down with your own skin. Given a few centuries of the same daily motion, it would vanish entirely.
The lock still turns because the pattern lives in what remains: a specific arrangement of cut depths, matched to a specific spring-loaded barrier, a physical password no wider than a pencil.
You keep asking why losing them feels like losing something larger. The answer is just information density. That small brass edge encodes exactly one configuration of matter the universe will admit through, and you carry the only copy in your pocket, alongside forty grams of exploded star.