Sometimes we over expect with the people we don't know. There is great diversity in the behaviour of people. Remember never understand people according to what you think about them instead understand according to what they assume about you. If a person is avoiding you don't take it to your heart. Be normal. If you become upset or irritated and show reaction it means the other person succeeds in his or her ill will. Just show that you don't care if they care not. Time will come the other person will realize his or her mistake and begin to think and do just as you want.