functional or dysfunctional family

What really makes a family functional or dysfunctional?  Everyone thinks different and to someone your family may seem dysfunctional but to you it can seem functional.  I always put my son's needs before my own needs and I think that I have a functional family but others might not.  In the Glass Castle the kids have gone without food or good clothes.  I don't think they had a dysfunctional family because they made it work and they were usually happy.  I guess it all really comes down to what people think.  It also shouldn't matter what other people think of you.  As long as you and your family are happy there is no way people can say your family is dysfunctional.