What is the origin of the idiom "get a life" and when to use it?

The idiom "get a life" likely originated in the latter half of the 20th century and is closely associated with informal and colloquial language. It emerged as a way to advise or criticize someone who is overly focused on trivial matters, gossip, or the lives of others, often at the expense of their own personal growth or interests. The expression is used to encourage individuals to pursue more meaningful or productive activities, rather than being preoccupied with unimportant or intrusive aspects of other people's lives.