[Note: I've been trying to make this a nice, neat post on the subject, but the more I work on it, the more it seems to grow like a patch of tangle-foot. So I'm just going to throw it out there as is.]
No, really. Have you given much thought to the reason for this practice? Why do we pray? To tell God what our concerns and joys are? We certainly seem to do that in prayer, but he already knows. (The Lord knows the thoughts of man Psalm 94:11a)
If God already knows, what is with this exercise in repeating it? Let me ask another question, is the purpose of prayer to make God aware of what is on our mind, or is it to shape our mind toward God's?
Prayer is a spiritual discipline. It is one of the 2 "primary" ones, along with reading of the scriptures. We practice spiritual disciplines rightly not to earn anything from God, because we can't. (Pelagius is still a heretic, despite his ideas popularity.) So why do we engage in spiritual disciplines?
To improve ourselves. To conform ourselves to Christ-likeness. Spiritual disciplines are also called "spiritual exercises" and I think that title is illustrative. I don't do push-ups because I think I will ever need to really do a push-up in any really life situation. I do push-ups because I understand it is a good and time tested way to develop my triceps and pectoral muscles so when I do need to use them for other tasks, they are fit and ready.
How does this apply to prayer? Well, if we hold that prayer is about shaping me and not shaping God, then it is a time to ingrain in ourselves what He wants for us and from us. I pray not because I have anything of value to say to the King of the Universe, but because, as his subject, it behooves me to listen to him.
Once we understand this dynamic of prayer, then our "shopping list" prayers suddenly become embarrassingly trite. Granted, we are commanded to pray for certain people. (1 Timothy 2:1-2) I think it is important that we obey Scripture's command on this. The list presented does not include our cousin, our neighbor's dog or any of the other usual targets of our petitions, however. Rulers and those in authority.
Pray is not conforming God to my will, but allowing God to conform me to his will, and, if it be his will, to allow myself to be used as an instrument of that will.
Lex orandi, lex credendi--Latin for "the law of prayer is the law of belief." What this means, essentially, is as we pray, so we believe, so we pray.
If we only pray about the common cold and the weather, it would seem to reveal that we think God is some sort of cosmic personal assistant. I don't think any of us would ever state that blatantly, but to listen to prayers, sometimes we hear that very thing.
To start with belief--what we profess--scripture, the creeds, well-written prayers that address the majesty and sovereignty of God, this shapes us in a more deliberate way. A way that causes our praying to conform to our belief.
An interesting exercise might be to write out your prayers for a week, or a month. (Or even record them.) Then examine them--is the whole counsel of scripture being reflected? Is their confession? Repentance? Prayer for those in authority? For the church? For the lost? Do you address the Trinity? Our future hope? Our history as the people of God? Christ's birth, life, death, resurrection and ascension?
You may not hit everything every day, certainly not in great detail. But are you getting a balanced diet? If lex orandi, lex credendi is true, and I think it is, then the implication would be in order to have orthodox belief, we must have orthodox prayers.
God used a year in Iraq to bring me to this place. It was no secret what my concerns were--I didn't want to catch a rocket on my way to the latrine in the morning. But that seemed a pretty shallow prayer life, as heart-felt as it was. I began writing out a daily prayer. I included Saint Patrick's Breastplate as the core of it.
I modified and shaped it over the remainder of my deployment. I found as I prayed the same thing day after day, the belief underpinning certain sections of it became clear, and I found I wasn't comfortable with all that at first sounded fine. I also began to deeply appreciate and learn from other sections.
This experience led me into the Book of Common Prayer, which I now use daily. It is a time-tested method of prayer, predating Thomas Cranmer's work in the 16th century, for he edited, translated and reformed the liturgy of the hours that had been used by the religious for over a thousand years before him, and still used by large sections of the church.