Wiktionary
prov. People have roles to play in life just as actors do in the theatre.
Wikipedia
All the World's a Stage is a double live album by Canadian rock band Rush, released in 1976. The album was recorded at Massey Hall in Toronto on June 11, 12, and 13 during their 2112 tour. The title of the album alludes to William Shakespeare's play As You Like It, which would again be referenced by Rush in their 1981 song " Limelight".
"All the world's a stage" is the phrase that begins a monologue from William Shakespeare's As You Like It, spoken by the melancholy Jaques in Act II Scene VII. The speech compares the world to a stage and life to a play, and catalogues the seven stages of a man's life, sometimes referred to as the seven ages of man: infant, schoolboy, lover, soldier, justice, Pantalone and old age, facing imminent death. It is one of Shakespeare's most frequently quoted passages.
"All the World's a Stage" is the 16th episode of the fourth season of the American comedy-drama series, Ugly Betty, and the 81st episode overall. It originally aired on ABC in the United States on 17 March 2010.
Usage examples of "all the world's a stage".
The one with the rifle and the walkie-talkie said, 'All the world's a stage, and all the men and women merely players.