Definiția și Sensul lui "(as|) (happy|merry) as a cricket"

What is the origin of the idiom "happy as a cricket" and when to use it?

The origin of the phrase "happy as a cricket" can be traced back to the association of crickets with cheerful sounds and pleasant weather. This idiom is used in informal contexts to describe someone who is extremely joyful, content, and in high spirits.