No one to replace the fish
There’s a scene in Lexicon by Max Barry in which Emily is sitting in a waiting room watching a single fish swimming in the upper half of a tank shaped like a large hourglass. The water drips slowly into the bottom half. Emily assumes that the whole mechanism will automatically pivot at some point and then the fish will be swimming in the bottom half. And so on, indefinitely. She figures it’s some sort of art piece. Looking more closely, she realizes that there is no mechanism for allowing the tank to pivot and that someone must just come in and replace the dead fish each day. ...