Without a god, we control our own destiny. A lot of things are currently awful, but with enough human ingenuity, we can overcome them.
On the other hand, if our fate is determined by a god driven by its own motives, we have lost control of our destinies to something that evidently doesn't care about us.
We would be ants on the back of a whale that might decide to dive at any moment, doomed perhaps to see our loved ones swirl away screaming into the watery void, on whale's whim, pointless.