One could compare healing to salvation, in that those that believe will be saved. People point to experiences where a person did not get healed, and use this as to say, "See, healing is not in the atonement. Jesus didn't purchase healing for all." The issue is that our experience cannot trump God's word and that itself is a position of faith. Can you imagine? Your experience doesn't line up with God's word, yet you still proclaim it to be true? People may think you're mad, blind, indoctrinated, and just plain nuts. To allow a book to define reality as opposed to reality itself (or circumstance). Is this insane?
Had Peter just stuck with reason, looked at the laws of this universe, he wouldn't have walked out on the water. It doesn't make sense scientifically to simply walk on water. Yet, belief is so very important to experience. All reality might very well be perception, and one is simply bound by those beliefs. We put ourselves within boundaries of limitation simply by limited beliefs.
What I am getting at is that belief in God's word, that is true, is what should dictate the results of your experience. If God told you to stand before a tsunami and tell it to go back, would that be within the parameters of your paradigm? Would you believe? Could you stand there as a mountain of water raged towards you, you could taste the salt in the air, and yet proclaim "Go back!"?
Such things seem out of order, but in understanding, granted by God, we see things are as they are. The world is a playground, all obstacles only there to be overcome. Why? All things are possible with God. There is no problem of which God cannot solve. Belief, faith, and expectation (from the heart and mind) mold our experience, but such things are founded in God. They are strengthened when they are directed at the Lord. Know His will, believe, and it will be done.