What is the origin of the "in a fog" and when to use it?

The idiom "in a fog" has its origins in the literal experience of being surrounded by dense fog, which severely limits visibility and makes it difficult to see and navigate. In a foggy environment, individuals can feel disoriented, confused, and uncertain about their surroundings, which likely led to the figurative use of the expression. The phrase "in a fog" is used figuratively to describe a state of mental confusion, disorientation, or bewilderment.