Sweetest Day is celebrated on the third Saturday in October.
It is rumored that in Cleveland 1921 a supposed candy shop employee called Herbert Birch Kingston went around giving candy to poor children, orphans, sick children and any other children that he thought needed some cheering up.
After spreading all this joy he mysteriously disappeared.
Never to be seen again.
Was he a real human being, or just a marketing stunt or a manifestation from the Flying Spaghetti Monster because it is well known that He created pirates as sacred creatures that hand out candy to children.
However, in 1922 The Sweetest Day in the Year Committee claimed all credit of distributing the candy and declared an annual Sweetest Day where people give candy to someone they think is the sweetest, so that more candy would be sold.
If you dislike commerce, then you can still take advantage of the other definitions of what is “sweet”