Quotes Uncovered: Dying for Opinions and Making History

A while back, I invited readers to submit quotations for which they wanted me to try to trace the origins, using The Yale Book of Quotations and more recent research by me. Hundreds of people have responded via comments or e-mails. I am responding as best I can, a few per week.
Mitch asked:

My Dad had one I always liked: “Any time two people always agree, one of them is doing all the thinkin’.” Any idea where that came from?

The Yale Book of Quotations has the following similar line:

“When two men in a business always agree, one of them is unnecessary.” William Wrigley Jr., Quoted in Reader’s Digest, July 1940.

Emily asked:

I’ve seen “Well-behaved women rarely make history” attributed to pretty much every “empowered woman” historical figure you can think of. Do you know who actually said it?

Yes I do. It was Laurel Thatcher Ulrich, in her article “Vertuous Women Found: New England Ministerial Literature, 1668-1735,” American Quarterly, Spring 1976 (“Well-behaved women seldom make history; against Antinomians and witches, these pious matrons have had little chance at all”).
Lars Erik Morin asked:

Voltaire is blamed for a phrase that goes something like this: “I’m very much opposed to your opinions, sir, but I’m ready to die for your right to have them.” Did he ever say that thing? Did he meet Adolf Hitler?

No and no. The Yale Book of Quotations lists this under Evelyn Beatrice Hall, an English writer who lived from 1868 to 1919:

[Paraphrase of Voltaire’s attitude:] “I disapprove of what you say, but I will defend to the death your right to say it.” Evelyn Beatrice Hall, The Friends of Voltaire (1906).

Bartlett’s Familiar Quotations traces this to a letter by Voltaire to a M. le Riche, February 6, 1770, but that is based on a misreading by Bartlett’s of Norbert Guterman, A Dictionary of French Quotations. The quotation does not appear in Voltaire’s letter to Francois-Louis-Henri Leriche of that date nor anywhere else in Voltaire’s writings.
Do any readers have any other quotations whose origins they would like me to attempt to trace?