I remember this funny scene in a movie or show where two people (think a guy and a lady) apparently stumble upon as extras in a restaurant  while a crew is filming a commercial. The director tells them just act natural in the background. The couple apparently begin speaking loudly and laughing during the shoot. While you see them out of focused in the background. The director then tells them to not speak and just pretend to speak. But of course they go on an over react with stuff on the menu and we see them acting crazy behind the main actress. The directer get furious with them for not being able to follow simple directions.