Maybe this is because we have a tendency to look at past events and think that because they happened, they must have been God's will. But is it really true that his will happens by default in this fallen world? God's Word is our number one authority on his will, and it's filled with extravagant promises and assurances that God has our very best interests in mind.
The Lord's Prayer says: "Thy kingdom come, Thy will be done, on earth as it is in heaven." So we are to pray for God's will to be done, which implies that it doesn't happen by accident. Further, if God's will was done, this world would be like heaven on earth.
Cancer is not from God; he is the author of life, not death. Starvation, crime, divorce, illness--these are symptoms of a world ravaged by the curse of original sin: death. But through it all, we have the victory in Jesus Christ, who came to give us life, and give it abundantly.
God can take something evil and turn it around for our good. It's not our circumstances that determine happiness--it's the condition of our souls. So God may have to allow suffering to heal our souls. That's not pleasant, of course, but it's the only way we can experience the full joy of his salvation.
God's ultimate plan for us is to walk more closely with him, so when hard times come, we shouldn't just resign ourselves to them. We should pray fervently and commit ourselves more fully to God. It's easy to confuse complacency with true surrender to God. Complacency is giving up the fight, while surrender is to seek God's will diligently, opening ourselves up to the work of his Holy Spirit. It means trying to be thankful when circumstances go against us, because we trust that God has everything under control. It's the only way to live in the center of his will, and to "prove what the will of God is, that which is good and acceptable and perfect." (Romans 12:2)