Everyone is a ghost.
Everyone is a memory.
Who we thought people were are ghosts of who they have become. Sometimes this happens when we see past our own ideas of them. After we stop projecting what we want them to be. Eventually who we thought those people were stay in memory. Everyone is a ghost.
We are ghosts to ourselves. The way we change, the parts of us that get left in the past. These versions of ourselves we used to be, the versions of ourselves we learned from, the parts of us we have shed are ghosts.
Everyone who has died. Everyone we have met. Every idea we had about ourselves has become a ghost. A ghost will linger and haunt. It will remind us, remnants of past.
No one and no idea ever goes away, they just diminish into faint echoes of what they once were. Transparent like the rest of things that once were.