What is the origin of the idiom "happy camper" and when to use it?

The phrase "happy camper" originated in the mid-20th century in the United States, likely from the camping culture of that time. It suggests that those who enjoy camping and embrace the outdoor lifestyle tend to be happier and more content. It is frequently used in casual discussions about personal well-being, satisfaction with a situation or event, or to express contentment with one's current circumstances.