Many people find shadows kind of scary http://purpendicular.eu/minocycline/index.html , and they are a metaphor for the things that would bother you if you saw them regularly, or focused on them.
Some also find the sun on their face to be rather pleasant, when done in moderation. Put together, facing the sun puts your shadow behind you.
(And you are not afraid of your own shadow, are you?)
Keep your face always toward the sunshine – and shadows will fall