"It's easy to identify people who can't…

“It’s easy to identify people who can’t count to ten. They’re in front of you in the supermarket express lane” is a jocular line that has been printed on several images. The saying was credited to “June Henderson, quoted by Red O’Donncll in Nashville Banner” in The Reader’s Digest in 1984.

“M. Grundler” has sometimes been credited (incorrectly) with the saying, but only since about 2000.

Google Books
The Reader’s Digest
Volume 125, Issues 747-752
1984
Pg. 72:
It’s easy to identify people who can’t count to ten. They’re in front of you in the supermarket express lane. — June Henderson, quoted by Red O’Donnell in Nashville Banner

9 February 1985, Evansville (IN) Courier, “Scram-lets” edited by Clay R. Pollan, pg. 21, col. 1:
FRIDAY SCRAMLETS ANSWER
It’s easy to identify people who can’t count to ten. They’re in front of you in the supermarket line that says “EXPRESS.”

Google Groups: alt.fan.john-denver
Quotes (Was: Re: Help looking for a Midi)
LiteofVega
3/15/00
(...)
It’s easy to identify people who can’t count to ten.
They’re in front of you in the supermarket express lane.
—M. Grundler

Google Books
The Mammoth Book of Comic Quotes
Edited by Geoff Tibballs
London, UK: Constable & Robinson Ltd
2004
Pg. ?:
Lots of people can’t count to ten. They are usually the ones in front of you in the supermarket express lane.

Twitter
nowone1‏
@nowone1
It`s easy to identify people who can`t count to ten. They`re in front of you in the supermarket express lane. by M. Grundler
10:03 PM - 31 Mar 2008

Twitter
Mike Folsom‏
@MikeF_says
“It’s easy to identify people who can’t count to ten. They’re in front of you in the supermarket express lane.”- June Henderson
3:50 PM - 8 Mar 2009

Google Books
The Little Book of Humorous Quotes
Edited by Malcolm Kushner
Little Quote Books
2011
Pg. 3:
It’s easy to identify people who can’t count to ten. They’re in front of you in the supermarket express lane. ~June Henderson

Google Books
5,000 Great One Liners
Edited by Grant Tucker
London, UK: Biteback Publishing Ltd
2012
Pg. ?:
It’s easy to spot people who can’t count to ten. They’re in front of you in the supermarket express lane.

Twitter
Funny One Liners‏
@funnyone_Iiner
It’s easy to spot people who can’t count to ten. They’re in front of you in the supermarket express lane.
9:17 PM - 14 Jan 2018

“It’s easy to identify people who can’t count to ten. They’re in front of you in the express lane”