Entry in progress—B.P.
“Happiness often sneaks in through a door you didn’t know you left open” is a saying that has been printed on many images.
 
Wikipedia: John Barrymore
John Barrymore (born John Sidney Blyth; February 14 or 15, 1882 – May 29, 1942) was an American actor on stage, screen and radio. A member of the Drew and Barrymore theatrical families, he initially tried to avoid the stage, and briefly attempted a career as an artist, but appeared on stage together with his father Maurice in 1900, and then his sister Ethel the following year. He began his career in 1903 and first gained attention as a stage actor in light comedy, then high drama, culminating in productions of Justice (1916), Richard III (1920) and Hamlet (1922); his portrayal of Hamlet led to him being called the “greatest living American tragedian”.
 
12 October 1933, Pittsburgh (PA) Press, “The Truth About The Barrymores: Screen’s Greatest Lover Reveals Happiness With His Third Wife” by John Barrymore, pg. 21, col. 4:
After stumbling around looking for contentment for years I suddenly learned that you cannot find it by hunting furiously for it, like a puppy looking for fleas in a rug. Happiness sneaks in through a door you didn’t know you left open.