"For every complex problem, there is a solution that is simple, neat, and wrong."
-- The Internet.
H. L. Mencken said something very like this, and he is usually credited with the quote. However, this is an edit of the original version, an edit I have not been able to find the source for. The original Mencken quote is subtly different:
"Explanations exist; they have existed for all time; there is always a well-known solution to every human problem — neat, plausible, and wrong."
This first appeared in an November 16th, 1917 article in the New York Evening Mail entitled The Divine Afflatus. This was later republished in his collections Prejudices: Second Series (1920) and A Mencken Chrestomathy (1949).
This is a case where the misquote is quite a bit weaker than the original. The internet has decided that they don't want to analyse their solutions to all of their problems, just the 'complex problems'. The original also emphasizes that it is the 'well-known' knowledge that is wrong, while the internet, again, wants to refocus us on the oversimplification of complex problems. But perhaps the most drastic change is the simplification of explanation and problem to simply 'problems'. Explanations are things like science, religion, and narratives -- those things that are supposed to keep us from having problems. The internet did not want to question those. The internet wanted to question the 'problems' -- which would be those times, one assumes, when the explanations break down. Mencken seems to be saying something much stronger, that the explanations are already broken, whether we want to think about it or not.