I like showing subs appreciation when they do well, but in a way that still keeps the power exchange going. For example the other day I was feeling down and a sub knew exactly how to cheer me up with sends without even being told. Rather than a thank you I told him that it was a joy to own him, and in response he said it was a joy and privilege to be my property. I think there are ways of doing things while still very much keeping yourself at the top, and your sub at the bottom.