Possible Clues:

• Classic interrogatory ad slogan
• '80s Wendy's slogan
• Old ad question that's apt for this puzzle's theme
• "Waiter, isn't my steak ready yet?" (Wendy's)
• 'Waiter, isn't my steak ready yet?' (Wendy's)
• Slogan for a burger chain or a complaint department?
• Memorable fast-food ad question
• Slogan coined in '84
• 1980s catchphrase
• Classic ad line, and question you need to answer to find the hidden theme in four starred answers