"You know what thought did" is a catch-phrase addressed to someone who has just made a stupid mistake and attempted to excuse himself by saying "But I thought..."

Does anyone know the origin of this saying; in particular, does anyone know what thought actually did?

  • 22
    Wow, where have you heard this? I'm a native American-English speaker, and I've never heard that phrase before.
    – Chris
    Commented Sep 6, 2010 at 22:12
  • 3
    Its origin seems to be British English. Commented Sep 6, 2010 at 22:51
  • 5
    @Mehper C. Palavuzlar: I'm British English and I've never heard it before.
    – Orbling
    Commented Feb 23, 2011 at 0:27
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    -1 for accepting an answer which doesn't answer your question. No wonder a user was frustrated when he wanted to submit his contribution: I cannot post an answer because I do not have the necessary rep that is why this question is a duplicate.
    – Mari-Lou A
    Commented Apr 23, 2017 at 8:10
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    @ChrisDwyer I'm so glad you haven't. It was addressed scornfully to children in the 1960s and 1970s in Australia. Most of the oafs - the usual drunken "grownup" that was wonted in the "culture" i grew up in - who used the phrase would have had not the tiniest whit of an idea of its origin. They just used it as yet another way to berate a child. Most of the knuckleheads who used it are thankfully worm food now or at least well into their 80s. And so they deserve to be. And i ended up migrating to the other side of the planet. Commented Mar 19, 2021 at 22:17

2 Answers 2


This was a common one in our house while I was growing up. The next line was "Followed a muck cart, and thought it was a wedding". I've no source, but a quick googling suggests we weren't the only ones.

  • The variant used by my mother (and apparently fairly common in Scotland and northern England) was "... planted a feather and thought it would grow into a hen". Commented Jan 26, 2011 at 15:03
  • 3
    This doesn't even attempt to explain the origin of the saying.
    – Mari-Lou A
    Commented Apr 23, 2017 at 8:08
  • No, but it does answer the OP's question "in particular, does anyone know what thought actually did?"
    – Simon
    Commented Apr 23, 2017 at 10:45
  • In my family, I always heard the answer as "jumped on a mutton cart, and thought it was a wedding", although I may have misheard "muck" as "mutton" as a child. It's strange that our two versions are so similar. I'm interested where you are from - I grew up in Chester, but my late father (who regularly used this phrase) was originally from Ripon. Unfortunately we are still not any closer to finding out where this phrase originated.
    – Kidburla
    Commented Jul 17, 2019 at 14:39
  • This from Never Play Leapfrog with a Unicorn - Page 93 is a typical citation from Google Books: “You know what thought did don'tcha? He shit himself and thought someone else did it,” she said, followed as always with the look of a learned philosopher. I don't know why all the obviously relevant scatological responses to this question have been deleted. Commented Jul 21, 2021 at 1:31

The Dictionary of Catch Phrases states that the original form of "You know what thought did?" is:

What did thought do?

and was exemplified in Jonathan Swift's, 'Polite Conversation', 1738

LADY ANSWERALL: I thought you did just now.
LORD SPARKISH: Pray, Madam, what did thought do?

It's also seen in Lincolnshire Traditional Sayings And Proverbial Expressions.

When a child says "I thought so and so" the adult may respond with, "You know what thought did? He only thought he did." A teenager, however, may reply, "Ah, but when he looked he had!" — a riposte which has the effect of counteracting the adult's attempt to control behaviour.


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