When you are being sincerely kind to that person, usually they learn from you. Then they become kind to you, but sometimes it takes time.

When you practice patience, it is unbelievable. Patience brings success and happiness in this life and in future lives, for hundreds of thousands of lifetimes. Through the development of patience, you can achieve enlightenment and free yourself from the oceans of suffering of samsara. Also you can enlighten the other person. With bodhicitta, you can utilize the harm to achieve enlightenment and the happiness of every sentient being of the six realms. You can benefit them like that.

In Sydney, Australia, I heard about one family that bought a new car. The neighbor did not like the family and he made marks on the car once or twice. Then the mother of the family asked a Dharma student what to do about this. The student explained to the mother what he thought I, Lama Zopa, would do to the neighbors who were marking the car. He thought I would buy them a present, whatever the enemy would like.

The mother checked what the neighbor would like and it seemed he would like a ball very much, so she bought a few balls. In the beginning he did not accept the balls, but then he accepted them. He was very happy and he erased the marks he had made on the car.

Your friend who is angry toward you, that means she is most kind to you, if you use the opportunity to practice patience or compassion toward her. Then you will be able to achieve enlightenment quickly; you will be able to liberate mother sentient beings from the oceans of suffering of samsara and bring them to full enlightenment. If someone is only nice to you, flattering you, giving you food and so forth, that just brings attachment and it becomes the cause of samsara and rebirth in the lower realms.