Why doesn't god use his magical smite powers to do nice stuff instead?

When bad things happen that aren't of human cause (so they can't blame it on us sinning), usually a Christian's excuse is "he works in mysterious ways, but we should trust his almighty power". If you ask me, that's plain bs. If a powerful politician makes a mistake, he can't just say "I work in mysterious ways" and have everyone understand and forgive him. If he really was real, and as amazing and loving and good as Christians claim he is, there wouldn't be natural disasters and global warming.