What is when someone says sweet dreams?

When someone says "sweet dreams", it is a common way of expressing a wish for a good night's sleep. The phrase is often used as a simple way to bid farewell to someone before going to bed.

The term "sweet" is commonly used to describe something pleasurable, enjoyable or pleasant. Dreams, on the other hand, refer to the imaginative experience commonly occurring during sleep. Therefore, when someone wishes "sweet dreams" to another person, they typically intend the phrase to convey a hope that the recipient will have a restful and positive sleeping experience.

The phrase "sweet dreams" is often used in Western cultures as a polite and friendly way of expressing concern for someone's well-being as they prepare to turn in for the night. It is typically offered in a casual manner, and often accompanied by a wave or a smile. Many people consider "sweet dreams" to be a comforting gesture that reminds them of the love and support of the people around them.