God answers our prayers for His glory. I think the greatest example of this can be seen in the life of Paul. In the book of Romans, Paul starts his letter with this prayer: "I thank my God for all of you because your faith is being reported all over the world. I remember you in my prayers at all times; and I pray now that at last by God's will the way may be opened for me to come to you I'm so eager to preach the gospel also to you who are in Rome." (Romans 1:8-15 NIV) Paul's dream was to preach in Rome. After he shares this, he writes, "Pray that I might have a prosperous journey." (Romans 1:10 NIV) Did God answer Paul's prayer? Yes, but not how Paul would have expected. Paul was arrested, put through the Roman court system and ended up as a prisoner in Rome. That hadn't exactly been his plan. Yet Paul wanted to go to Rome. He was willing to let God work it out in God's way. Paul probably never imagined that God would answer his prayer in this way. What did Paul do in Rome? He wrote a bunch of letters to different Christians all over the Mediterranean. We got the New Testament because Paul allowed God to answer his prayer in God's own way and His own purpose.
To surrender completely to God is our biggest need.