What is the origin of the idiom "shake like a leaf" and when to use it?

The idiom "shake like a leaf" is believed to have originated from the observation of leaves trembling or shaking in response to wind or external stimuli. It is commonly used in various contexts to describe a person's physical response to fear, nervousness, or extreme anxiety. This expression can be used in both formal and informal settings, such as public speaking engagements, job interviews, confronting phobias, experiencing a traumatic event, or being in a state of heightened anticipation.