Historical clue formulations

• "No joke!" — 2025-04-23
• "Seriously!" — 2024-06-17
• "Dead serious!" — 2021-04-25
• "No kidding!" — 2017-03-01
• "This is no joke!" — 2016-02-24
• "Seriously!" — 2015-07-13
• "No kidding!" — 2014-08-12
• "Seriously!" — 2012-11-13
• "Honest!" — 2010-05-30
• "For real!" — 2010-01-09
• "For real!" — 2009-10-22
• Follow-up to a parent's command, maybe — 2009-10-08
• "This is no joke!" — 2007-11-02
• No-nonsense cry — 2007-08-25
• "Seriously!" — 2006-12-01
• "Seriously!" — 2005-09-23
• "This isn't a joke" — 2004-09-26
• "This is serious!" — 2004-09-19
• "This is serious!" — 2004-07-25
• "This is no joke!" — 2003-09-18
• "You should listen to me" — 2003-01-24
• "No kidding!" — 2002-12-27
• "No kidding" — 2002-08-01
• "This is no joke!" — 2001-10-14
• "Don't play with me!" — 1997-07-05