Now it may surprise you to learn that in His efforts to get permanent possession of a soul, He relies on the troughs even more than on the peaks; some of His special favourites have gone through longer and deeper troughs than anyone else. The reason is this. To us a human is primarily food; our aim is the absorption of its will into ours, the increase of our own area of selfhood at its expense. But the obedience which the Enemy demands of men is quite a different thing. One must face the fact that all the talk about His love for men, and His service being perfect freedom, is not (as one would gladly believe) mere propaganda, but an appalling truth. He really does want to fill the universe with a lot of loathsome little replicas of Himself— creatures whose life, on its miniature scale, will be qualitatively like His own, not because He has absorbed them but because their wills freely conform to His. We want cattle who can finally become food; He wants servants who can finally become sons. We want to suck in, He wants to give out. We are empty and would be filled; He is full and flows over. Our war aim is a world in which Our Father Below has drawn all other beings into himself: the Enemy wants a world full of beings united to Him but still distinct.
Lewis, C. S. (2009-05-28). The Screwtape Letters (pp. 38-39). HarperCollins. Kindle Edition.
Suffering is a strange thing. Lewis talks about it as the "trough". In Letter 8 of "The Screwtape Letters" (Lewis' writes from the perspective of Screwtape, a demon who is writing to his nephew and protege as he works to derail the faith of a human) he contrasts what God wants for us, and what the realm of evil desires for us. The chief difference is that evil takes, and God gives.
The irony is that we would tell ourselves that if we can live how we truly desire, if we can make our own choices, if we can control our own destiny, then we will be a sort of pseudo-god; certainly we'll be the gods of our own universe. This was the lie that was told since the beginning, when the bond between God and man was shattered when man decided that instead of accepting the psuedo-God likeness he already had, he would attempt to replace it with an image he found more desirable. Rather than replace the image, what we found (and find, in our own lives), is that sin doesn't give us more identity, but actually robs us of our identity. The status we thought we'd gain turns out to be a lie. We end up being less ourselves than we would have been otherwise.
This is often the result of suffering. All that we would identify with begins to be stripped away and we find that at the core, in the deepest parts of our soul, was written an identity long ago that is more us than we have ever known; deep inside is the true us, the one that is now being filled again with the perfection of sons and daughters through Jesus Christ.
Screwtape would rather that men blindly give in to passions/desires/sin. God would desire that men willingly and gladly follow. They are replicas, but only because they are distinct.