"A smile is a curve that sets everything straight"

Smiles—such as “service with a smile”—can be an important part of business etiquette. “A smile is a curve that sets everything straight” is saying that was popularized in 1953-54. “A smile is just a little curve that keeps everything straight” was cited in print in April 1953.

American stand-up comedienne and actress Phyllis Diller (1917-2012) has been credited since the 1990s for the saying, but there is no evidence that she originated it.

23 April 1953, Portsmouth (OH) Times, “Minego’s Sports Gossip” by Pete Minego, pg. 14, col. 1:
A smile is just a little curve that keeps everything straight.

28 July 1953, Algona (IA) Advance, “Hodgepodge,” pg. 6, col. 1:
A SMILE IS a curve that enhances curves.

26 December 1953, Boston (MA) Herald, “Ching Chow” comic strip, pg. 11, col. 4:
IT IS TRULY SAID—A SMILE IS A CURVE THAT CAN SET MANY THINGS STRAIGHT.

17 January 1954, Boston (MA) Sunday Advertiser, “The Cheering Section” conducted by Bruce Patterson, Pictoral Review, pg. 9, col. 1:
A smile is a curve that sets many things straight.
Pensacola Gosport

6 May 1954, Elgin (IA) Echo, pg. 8, col. 6 ad:
“A smile is,a curve that sets many things straight.”
(Schori & Kuster Lbr.—ed.)

Google Books
Metropolitan
Volume 50
1954
Pg. 47:
“A smile is a curve that sets many things straight.”

Google News Archive
29 January 1959, Milwaukee (WI) Sentinel, “Dear Abby” by Abigail Van Buren, pt. 1, pg. 12, col. 5:
CONFIDENTIAL TO “UNPOPULAR”: A smile is a curve that can set a lot of things straight. Try it!

Google Books
Beauty Lab:
How Science Is Changing the Way We Look
By Mildred Dawson
New York, NY: Silver Moon Press
1995
Pg. 40:
“A smile is the curve that sets everything straight,” says comedian Phyllis Diller.

OCLC WorldCat record
A smile is a curve that straightens most things
Author: Bass Clef.
Publisher: [S.l.] : Blank Tapes, 2006.
Edition/Format: Book

Twitter
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“A smile is a curve that sets everything straight.” ~ Phyllis Diller http://bit.ly/okv9Cz #quote #SQN
3:30 PM - 12 Oct 2014