Psalm 13...

Psalm 13 begins with the verse "How long, O Lord? Will you forget me forever?  How long will you hide your face from me?"  Not an auspicious beginning, and if you think about it, kind of an arrogant one.  You have David, the man whose very position is his because of the direct intervention of God, questioning God directly.  You have a mere man, who is born and dies within the window of one-hundred years, questioning the God who spoke the entire universe into existence and still holds it together today (Genesis 1-2; Acts 17:28).  I don't know how your superpowers are doing, but I can't even speak my 4-month old kitten into not attacking my shoelaces in the morning.  As the Word says in Ecclesiastes 3:11(NIV) "He has made everything beautiful in its time. He has also set eternity in the hearts of men; yet they cannot fathom what God has done from beginning to end."  Mankind cannot fathom all that God has done; yet he seems constantly confident in challenging the all-powerful creator of the universe.  Pick most any significant figure in the Bible, and you're bound to find it somewhere:

1. Adam and Eve - ate the apple in Genesis 3
2. Abram and Sarai (Abraham and Sarah) - they both laughed when God, the creator of everything, said they would have a son together in Genesis 17&18.
3. Jacob - the man God renames Israel and is the one whose sons are the heads of the 12 tribes of Israel physically wrestles against God in Genesis 32.
4. Moses - whines about not being able to speak well when God Himself tells him to go into Egypt and free the Israelites in Exodus 4&5.

The list goes on.  The point I'm trying to make here is that David is not alone in questioning God.  Despite all we know about Him and how He has revealed Himself to us throughout history... we still can't seem to resist questioning His goodness and motives through our words and actions.  I definitely do this on a regular basis.  I seem to constantly fret about how to make ends meet with regard to money.  I used to always worry about my career choices and whether I was making the "right" decisions regarding the career choices I made.  I constantly fear failing at what I'm doing and wonder why God lets things happen the way they do.  I am not unique in this.  No one is.  After all, the figures I named above are among the most well-known in the Old Testament, and they are all on record, in the oldest known written text, for having complained about God, to God, Himself!

Psalm 13 ends with verse 6 "I will sing to the Lord, because he has dealt bountifully with me."  Dealt bountifully?!?  David spends most of the psalm complaining about how God was taking so long to deal with the evil men that were defeating him, questioning God's timing and seeming to try and hurry God along.  I don't know about you, but when I do everything I can for someone, giving them my best and being constantly concerned with their needs, and they still complain... it doesn't really motivate me to stick my neck out for them yet again!  Yet God was bountiful in giving good things to David.

And really... He's the same with us.  We have done just as much whining and complaining as David does throughout the Psalms.  We have done things we shouldn't have, said things we shouldn't have, thought things we shouldn't have... and desired things we'd be ashamed for anyone else to know about. Yet God, knowing every detail of how history would play out "sent his one and only Son into the world that we might live through him.  This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins" (1 John 4:9-10).  

To conclude... God does not deal with us as we deserve.  Because of Christ, we are able to stand in the presence of God, through prayer, and tell Him what's on our mind.  We are able to bring our fears and worries and stressors and failures to Him... and He does not see them as the irritants we see them.  He desires to hear from us, so as in the words of Paul in 1 Thessalonians 5:17(ESV) "Pray without ceasing."