If the first and lowest operation of pain shatters the illusion that all is well, the second shatters the illusion that what we have, whether good or bad in itself, is our own and enough for us. Everyone has noticed how hard it is to turn our thoughts to God when everything is going well with us. ... Now God, who has made us, knows what we are and that our happiness lies in Him. Yet we will not seek it in Him as long as He leaves us any other resort where it can even plausibly be looked for. ... The creature's illusion of self-sufficiency must, for the creature's sake, be shattered; and by trouble or fear of trouble on earth, by crude fear of the eternal flames, God shatters it "unmindful of His glory's diminution". Those who would like the God of scripture to be more purely ethical, do not know what they ask. If God were Kantian, who would not have us until we came to Him from the purest and best motives, who could be saved? And this illusion of self-sufficiency may be at its strongest in some very honest, kindly, and temperate people, and on such people, therefore, misfortune must fall.
-C. S. Lewis, The Problem of Pain
Everyone knows that God prefers the weak to the strong, the humble to the proud, the poor to the rich, the child to the philosopher. I was always under the impression that this was because God was egalitarian in a way that human society can never be, and judged people solely on their merits and not their social status, but C. S. Lewis would have his readers believe that this isn't the case. God loves broken people for the same reason that an abuser prefers to form relationships with people who have little education or life experience and don't have social support systems: they're easier to manipulate into a position of complete dependency.
When humans exhibit this kind of behavior, it is condemned as despicable and creepy and unhealthy; I'm not entirely sure why Lewis describes the same kind of behavior as one of the nobler characteristics of God. He goes on at length about how perfect God is, and how ugly and mean humans are, but even if you grant that humans benefit from a relationship with God no matter the circumstances of that relationship, I don't really see how it follows that we should accept that God causes us pain because he loves us. If there were a rich guy who took in poor kids, bought them clothes and tutors and vacations in Spain and improved their lives in a multitude of ways, but at the same time cut them off from their family so that they would be completely dependent on him, the good he did wouldn't outweigh the creepy abusiveness of demanding complete dependence.
Lewis is very clear that this suffering is sent by God with a purpose. Its not the direct result of sin, or the action of some other near-omnipotent godlike being like Satan or anything. This suffering is inflicted on good, "honest, kindly, and temperate people," so its not meant as punishment to direct people away from sinful ways. Lewis is clear that God's purpose in allowing suffering is to strip away every good thing in life so that people will have no sense of self-sufficiency, no sense of control, no sense that there is any hope of joy in anything but Him. I guess whether or not you see this as psychopathic behavior depends on whether or not you think that its true, that there is no hope of anything positive apart from God. Clearly Lewis thinks that this kind of behavior is admirable and holy. I can't help but think, though, that even if its true that there is an almighty God who knows that humans can only be happy when they're with him, that doesn't make manipulating people with all the horror the world holds into something pure and holy.