Walk A Mile In My Shoes

The phrase, "Walk a mile in my shoes,"  is commonly used.  But it is used in such a sense that no one really knows the true meaning behind it.  Many would say it means that you do not know what I have been through, until you lived it, but what really gets me is how this is almost impossible, unless we are able to turn back the hands of time.  I mean to live a day over again, with everything being exactly as it was before.  Is there not another term that we can use instead?  Like, "I have been through a lot in my life, some of it would be too hard for you to understand."  The ending, bringing me back to my first post on how fully understanding life is impossible.  Life brings many limitations, and this is one of them.