1 general:: Acquire some interests or relationships of one's own. For example, Stop sitting around and complaining? get a life. [Slang; late 1900s]
American Heritage Idioms
2 general:: Phrase(s): Get a life! Inf. Change your life radically! Find something interesting to do or say! • You are such a twit! Get a life! • Get a life, you clown!
McGrawhill's American Idioms And Phrasal Verbs