“Keep your face always toward the sunshine, and the shadows will fall behind you.” ~ Walt Whitman
A shadow can be a metaphor for the things that would bother you. Yet it is the sun that produces the strongest shadow of all.
Still, many people find the sun on their face to be rather pleasant and instinctively seek it out, even if ever so briefly.
The result is, literally, that your shadow will fall behind you, out of sight [out of mind].
To have things fall behind you represents the past, especially a forgotten part of the past, as in forgotten by choice.
It is a way of bringing optimism into your life easily.
image source: I Love Quotes