The keys don't fit, and I'm no longer sure I want them to

I'm walking the tier at night with a full ring of keys on my hip, old brass ones I could read by touch after thirty years. Every lock I try, the key goes in halfway and stops — not the wrong key, just not mine. I used to wake up sweating from this one. Lately I just stand there in the dream, holding the ring, thinking: at least I know every lock I've ever failed to open.