What is the origin of the idiom "misery guts" and when to use it?

The term "misery guts" is a colloquial phrase that combines two words: "misery" and "guts." The origin of the phrase is uncertain, but it likely emerged as a playful and informal way to describe someone who is consistently unhappy or miserable. It is used to describe a person who is constantly gloomy, grumpy, or prone to complaining. It implies that the person's disposition or attitude is characterized by a lack of joy or contentment, as if their guts are filled with misery.