Quotes Uncovered: Playing Cards With Doc and Eating at Mom's

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.
Casey Frank asked:

[Who said] “England and America are two countries separated by a common language”?

The Yale Book of Quotations has the following two quotes:

“England and America are two countries separated by the same language.” Attributed to George Bernard Shaw in Reader’s Digest, November 1942.

“We have really everything in common with America nowadays, except, of course, language.” Oscar Wilde, The Canterville Ghost (1887).

Grant asked:

I’ve been trying to find a source for the following: “Dream no small dreams for they have no power to move the hearts of men.” It’s often attributed to Goethe or Hugo.

The Yale Book of Quotations, which attempts to trace all famous quotations to their earliest findable sources, has this:

“Make no little plans; they have no magic to stir men’s blood.” Daniel Burnham, quoted in Collier’s, July 6, 1912.

Burnham was a prominent architect.
JJG asked:

There’s an advice triad, where the third line gets altered to fit the circumstance, but the first two are:
“Never play cards with a man called Doc,
Never eat at a place called Mom’s,
and never …”
Do you know the origin?

Yes, I do. The YBQ cites it thusly:

“Never play cards with a man called Doc. Never eat at a place called Mom’s. Never sleep with a woman whose troubles are greater than your own.” Nelson Algren, A Walk on the Wild Side (1956).

Do any readers have any other quotations whose origins they would like me to attempt to trace?