Many years ago when I became heavily involved with the sport and hobby of dogs, I also went to work at a very busy veterinary hospital. This opportunity gave me a unique point of view. I learned about the good of a owning and loving a dog and also just how bad it can go for a dog and how often that happens. 
With a little bit of deliberate thought and process you can select a family dog that will fit in and become a part of your family with as little struggle and issues as possible for you and the dog.