I thought of all those biblical anecdotes of people believing in Christ's ability to heal/resurrect/etc. and how the moral of the story is always: have faith and you will be rewarded for it. Who believes like that these days? When something doesn't go as you hoped (and prayed for), it's probably not God's will and who are we to presume to tell him what to do? That or, you didn't have enough faith. But that sort of faith also requires faith in your own judgment of how things should be, and most people don't have that, rightly so.
Maybe impure motives get in the way. What's a pure motive then? When does something you hope for not benefit you, and how can you ever be unbiased under those circumstances? I suppose it's all smoothed over if you stick to a vague sort of faith that he'll make sure everything turns out for the best after all (even if you don't agree), but it seems like such a far cry from the days of the woman who touched Jesus's garments wholly believing it would heal her, and it did.