It only occurred to Alexander the Great when he accosted the Greek philosopher, Diogenes. Lying in the sun, standing near him with his shield-bearing guards, Alexander wondered if the destitute wiseman had ever desired anything in his life. Ready to part away with his enormous wealth, the response was anything close to it. Diogenes instead wanted the monarch to pull way his shadow from himself "stand a little out of my sun." Dismayed to hear the request, Alexander thought it for a while but at the end admired the haughtiness and grandeur of the man.
What if the monarch's shadow was not present or he didn't have any of his own? Though shadows are known to be useless, but it did help Alexander the Great fulfil a desire. Come to think of it, shadow may not do anything substantive, but it extends unconditional support even as one ventures out or is in the company of others. It is true that people all have shadows with them, whether or not they liked, in different shapes and sizes during the day. Diogenes tried to disassociate the monarch from his shadow, and in doing so made it worthwhile for himself. Alexander was unconscious of his shadow, till he was made conscious of it.
For psychologists, shadow is a sub-conscious aspect of the personality that one cannot even consciously get rid of so easily. Only once life is bereft of its shadows, one really understands that shadows do carry their own weight. One needs to feel the weight because in reality there might not be any. In the same way as gravity seems part the planet and for reasons is often taken for granted. Same holds good for a shadow, without doubt an essential companion like a faithful canine. One can't step outside without a shadow, especially when you've spent so many years together with it and grown up close.
However, for a shadow a day is too long for extending an incessant company. Need it be said that a shadow to move along with a body during the long day may be tiring. Therefore, it needs to take a break. And it does so when it is completely dark, the shadow takes complete rest with the body. A person and his shadow are never pulled apart, both merges as one but that the merger is indeed a period of loneliness. It is a common human experience that can affect people of all ages and backgrounds.
Shadow poses many possibilities. If shadow has only abstract meanings, then why doesn't everyone get rid of it? The trouble is that they don't know how to. But even if they did, I doubt anyone would discard their shadow. Simply put, because people are used to them whether it serves any purpose or not. And if our shadows are allowed to separate from us, shadows will continue to exist without any control. Hard to believe it.
But if it was to separate from the body, it would be hard to imagine how it might I look like. It might be like a pair of discarded old shoes.