I agree there can be an important role for affection at least. I find that My slave becomes more emotionally attached and eager to serve and please Me through the process of training and Domination. As he is dominated he becomes more submissive and falls deeper into worship and love. But I also find I have to keep a certain reserve if I am to extract from him the service I require and if I am to impose the punishment he needs (and desires) as part of his training (along with a little loving tender care, of course) I regard him as a precious pet or toy. Perhaps that is more of a Femdom point of view. I believe a little rigor is required. But everyone has Her/His own style of dominance.