Saintly Sugar

Poor Sugar is such a saint. He really likes the goat, Ria, and calls for her if I take her away from him, but she is mean to him. She is super sweet to people, but although the pony is nice to her, she seems to be bothered by him. I am new to goats... so maybe those of you who are more familiar can fill me in. What exactly is she doing? Why is she doing this? When will she stop?