Regarding unanswered prayers, I've heard quite often in the Church that people don't have enough faith. There tends to be two different meanings to this statement. The first is that people are not trusting the evidence that they have that God is trustworthy when it comes to the unknown. The second is that people aren't trusting God to give them what they want.
I don't have a problem with the first; its the second that causes serious issues both inside and outside the Church. In the previous post (What is Faith?) I had mentioned the importance of knowing the nature of the person that we are looking to put trust in. If you don't have a proper understanding of that person's character, then any trust is likely to fail us. In the case of the second statement, if we believe that by placing faith in God we will be made healthy or rich, we are bound to have our faith in God shaken or even destroyed.
If we have a proper understanding of God (that He is more interested in shaping our character to be more like His for an eternal relationship with Him, than our current comfort level), then we will realize that pain and suffering are actually a boon. Unfortunately, the wrong idea of what faith in God should produce is coming from both inside and outside the Church. The entire culture is obsessed with the individuals' existential pleasure. That obsession is reflected in our theology (See "God You Way, Right Away"). This cultural permeation of the Church has caused many to teach that God always wants us to be healthy and be monetarily secure.
Many Christians have recognized that this "health and wealth" "gospel" is a false gospel and have labeled it as such. However, the real danger comes when Christians who would not verbally accept that false gospel, yet tell people that the reason they are sick or are in a financial hardship is because of their lack of faith. Most of the time the implication is that if the person had enough faith, God would heal them or give them a truck-load of money to fix the problem. When the person is not healed or does not get relief from the economic hardship, they lose their reason to trust God, and I've seen some completely leave the faith.
On the other side, though, this is true in a sense. The reason that God puts us through hardships is precisely because be don't have enough trust in Him- we are still trusting in ourselves (an untrustworthy source). But just because we start to exercise our faith, that does not mean that God will immediately pull us out of whatever discomfort we are experiencing. God's molding us into the character of His Son is not a one-time investment; it is a life-long commitment. If it were a one-time investment, man would take credit for passing the test, then slide back into a life that is everything but reflective of God's character.
As a Christian who wishes to grow in my faith, it is important for me to understand this part of God's character. As a defender of the Christian faith, I must understand what I am defending before I can defend it. Also, if someone is arguing against the Christian faith, they must recognize that this is the character of the Christian God and argue against it, not some strawman. Pain and suffering are not a problem in the Christian worldview.
I must understand the true character of man as a morally fallen being in order to relinquish my trust in man (thus increase my trust in God); while the non-Christian must understand that a morally corrupt nature being the character of man is part of the Christian worldview, and argue against that. If man is not morally corrupted, it follows that there is no need for Christ's sacrifice. It also follows that man can choose his own way to God- if not exalt himself as God. However, if man's nature is morally corrupt, then it follows that we may only come back to God on His terms.
Is Faith Emotional or Logical?
What is Faith?
Is Blind Faith Biblical?