“Service with a smile”

It's not known when the "service with a smile" slogan was first used, but it appears in an ad for the Abraham & Straus (A&S) store as early as 1915.

28 November 1915, New York Times, pg. X1 ad:
Abraham and Straus
Brooklyn
(...)
Service With a Smile
to make your Christmas shopping easy.

5 December 1915, Atlanta Constitution, pg. 8 ad:
Jacob's Pharmacy
(...)
SERVICE WITH A SMILE
to make your Christmas shopping easy.

19 February 1925, Life, pg. 5:
"Service with a Smile"
(It's the slogan of all up-to-date stores, but what will be the effect on the clerks? This?)