What is the origin of the idiom "like a bump on a log" and when to use it?

The idiom "like a bump on a log" is believed to have originated in the United States in the 1800s. Since Bumps on logs are simple, basic shapes with no complex functions, comparing a person to one suggests they are doing essentially nothing of significance, but just sitting or lying around idly and motionlessly, resembling an inanimate protrusion on a piece of wood.