What would happen if all your prayers were answered? The whole plan of God would be annulled, that's what!
"Now, we find many people critical when a righteous person is killed, a young father or mother is taken from a family, or when violent deaths occur. Some people become bitter when oft-repeated prayers seem unanswered. Some lose faith and turn sour when solemn administrations by holy men seem to be ignored and no restoration seems to come from repeated prayer circles. But if all the sick were healed, if all the righteous were protected and the wicked destroyed, the whole program of the Father would be annulled and the basic principle of the gospel, free agency, would be ended.
If pain and sorrow and total punishment immediately followed the doing of evil, no soul would repeat a misdeed. If joy and peace and rewards were instantaneously given the doer of good, there could be no evil - all would do good and not because of the rightness of doing good.
There would be no test of strength, no development of character, no growth of powers, no free agency, no Satanic controls.
Should all prayers be immediately answered according to our selfish desires and our limited understanding, then there would be little or no suffering, sorrow, disappointment, or even death; and if these were not, there would also be an absence of joy, success, resurrection, eternal life, and godhood."
Spencer W. Kimball, Improvement Era, March 1966
Once we understand God's plan for us, we will understand why there must be trials in this life and why He can't give us everything we want.