I only know a part of Sophie's story.  I have almost always had two dogs.  When one of my dogs died, the other could not stand to be alone, so we went looking for a companion for him.  He was part border collie so we called Border Collie Rescue of Washington. 
After talking for a while, my contact brought Sophie over for a visit.  We were told that Sophie had been found abandoned on a highway.  She was placed with one family, who kept her tied up outside all day and complained when she got excited at night.  Fortunately, we have a fenced yard and constant access to and from the house.   From the first Sophie was the perfect dog for us.  She was very well trained (not by us).  She will go any pace her companion goes on a leash.  She had to learn to retrieve, it is not really her bag, but she is very good humored about it.  She only barks when she is playing fetch and that is something taught her by my old dog.
For the first six months or so we couldn't believe our luck.  We thought someone would show up to take her away from us.  She is great with children of all ages and loves snuggles. 
She has now been with us for 4 years and I can't believe it has been so long.