What is a good/godly way to deal with a person who is very demanding?

Ask God to show you how He sees her. I worked with a woman that was mean to me all the time at work. I saw her how God saw her.... a tree dying and starving for water. God gave me a love for her that was more than I could understand and funny thing, she came in one day and said, I've decided to be nice to people and by the time I left there, we were actually friends. God changed my heart and in the process He changed her attitude.