There is a native Indian saying: "Trust in G-d, but steer away from the rocks." Of course we must trust that G-d has a hand in everything, and that His plan will unfold in the way He has set out. But I believe that we are so far removed from understanding the complexity of G-d and His methods. So if three thugs jump out of a car to attack me, it would be foolish for me to think that I should do nothing, as G-d's Will will be done.
G-d may have a hand in the minutae of everyday life, but He gave us free will. Free will, will inevitably make outcomes unforeseeable. I can trust that there will be ultimate justice. I can trust that G-d has created things that are far beyond my comprehension, but that they are ordered. And maybe in the Olam Haba, I will come to know G-d's ways, but for now, I have to put my free will to the best use possible.
One other thing, just because there is imperfect justice in this world, which will ultimately be rectified, does not mean that there is no meaning in this world. We must realize that although we may not achieve perfection, justice, harmony, and so on, that there is still meaning in striving for it, as we are now on this temporal plane.