What’s the last thing you lost that you didn’t miss until it was gone?

Just spent two hours tracking down a container that vanished for a week—no, not literally, but in the system. It turned up in Rotterdam with a different bill of lading. I’m not even mad. I just keep thinking: what small thing did I lose this week that I’ll only notice when it’s gone? A pen? My train-of-thought? The exact shade of blue in my coffee this morning?