Job 6:8 "Oh that I might have my request; and that God would grant me the thing that I long for!"
Job is about to make a request in the verses that follow this one that he thinks he means (that God would cut him off, basically he is asking God to take his life). It is a request that is borne from his present circumstances and even though it seems right now it is not the right prayer. We understand completely why he feels it is the right prayer (anguish and suffering birthed it) but it could not be more inappropriate in light of what God intends to do in him and through him. There are prayers we will pray throughout our lifetime that we should get down on our face before God and thank Him that He did not answer. I remember a pastor telling me once that when he was younger he prayed earnestly for God to take him down a certain course (before he was a pastor) and he began to get frustrated with God because it was not coming to pass; it was a path after his own hearts desire for his future. He confessed later that he thanked God earnestly that He did not answer those prayers because otherwise he would have never met his wife, never had the family he has and would have in all probability not been in the ministry today. It would have taken him on another course altogether.
I preached a message some time ago on "Jesus' Unanswered Prayer"; I think the title caused people to pause for a moment and ask themselves, "Wait, Jesus had an unanswered prayer; is that possible?" But, not only was it possible, it happened. It was a prayer that was borne out of His anguish as a man and yet to answer that prayer would mean missing the Fathers will for His life and so, He realizing that, ended His prayer with "Never the less, not my will but thine." We are, of course, talking about His prayer in the garden when he sweat drops of blood. His soul was in anguish and He prayed that if it were possible that the cup would pass from Him. Yet we all know, this was the very reason he was born into the world, to drink that cup. The Father could not answer that prayer (and it must have been emotionally painful to the Father to know He could not answer this request of His beloved Son).
Now, let's bring this into modern times, into our own lives. Do we know the absolute will of God for our lives? No, in most cases we have an idea of His will and we sense a direction but we do not usually know specifics and so we pray many times based on our perceived needs. But may we always find the grace and presence of mind to say at the end of our prayers, some of which will be borne out of anguish, never the less not my will but thine be done!