Frustration and bitterness were not Paul's companions. He did not make what he considered to be his needs absolutes in order to determine his sense of well-being. By faith, he believed that God was watching over his life and would provide.
Paul followed the example of Jesus Christ, and this is the example that we too are to follow. We are to learn to be angry and not sin. We are to learn not to make frustration, bitterness, and hostility regular parts of our lives.