Dogs have given us their absolute all. We are the center of their universe. We are the focus of their love and faith and trust. They serve us in return for scraps. It is without a doubt the best deal man has ever made.
To be rejected by someone doesnt mean you should also reject yourself or that you should think of yourself as a lesser person. It doesnt mean that nobody will ever love you anymore. Remember that only ONE person has rejected you at the moment and it only hurt so much because to you that persons opinion symbolized the opinion of the whole world of God.