Since this is a specific and recurring kind of annoyance, at least for me as my brain enters its twilight years, I thought I'd start a separate thread for it.
Where did I put the backpack I use for marketing? It isn't where it goes. I know I brought it back from the Greenmarket this morning, because I unloaded my purchases into my refrigerator. But then where did I put the backpack? (Yes, I looked in my refrigerator.)
How could I lose a fucking backpack? Where could I have put it that can't be seen?