The worst blasphemy is believing that the handiwork of god is defective or tainted.
Right answer, wrong question. God's work is by definition perfect. If we consider strokes or heart attacks or childhood cancer "defects" or "taints" it is not because they are unplanned; it is because they are part of a plan we do not and cannot see.
The world is full of people who pray for the winning lottery numbers, or the next rent payment, or even the next meal. But if you truly believe that an all-seeing, wholly benevolent god is holding the reins of the universe, that his eye is on the sparrow and nothing happens but according to his plan, there is only one prayer that is appropriate:
Thy will be done.
That's it. Beginning, middle and end.