Liking as I do the aesthetics of Madoka, and also the only other anime I'd seen by Shinbo/Shaft, Dance in the Vampire Bund, I naturally sought out Shinbo's pre-Madoka hit, Bakemonogatari. I'll do a proper review of that once I've finished watching it (I'm halfway through), but suffice it to say that it's a collection of linked stories in which a high-school boy, Araragi (a recovering vampire), encounters a number of girls who have had troublesome encounters with theriomorphic spirits, often amounting to some kind of possession.
Anyway, one of these girls is basketball whizz Suruga Kanbaru, whose left arm has turned into that of a monkey. At first it was simply a monkey's paw that she inherited and kept in a box, but after reading W. W. Jacobs and wishing to be the fastest runner in her class she found that all the girls who were faster than her were mysteriously attacked in the night, knocking them out of the running, as it were. It was at that point that the paw attached itself.
First - I was surprised (but Japan never ceases to surprise me in this way) that W. W. Jacobs' story was well known enough in Japan to get an explicit name-check. I read it when young, when I was gobbling up M. R. James and his ilk, and it certainly stayed with me, but I don't remember hearing it mentioned much in the intervening years. How famous is it?
Still, I suppose the device of the badly-framed wish has a much longer history, whether it's misinterpreted through a kind of jobsworthy punctiliousness (as in the sorcerer's apprentice) or malice (as in the monkey's paw). Of course, anyone who has ever struggled to write a computer program will be familiar with the ease with which one of these can seem to slide into the other.
Suruga naturally attributes the injuries of her classmates to the monkey's paw. What's interesting is that she is wrong. The entity that attacked them, and that has attached itself to her, was actually a "Rainy Devil", the nature of which is also to grant wishes in a tricksy (but differently tricksy) way. The Rainy Devil knows that wishes have both a surface and an underside, and it's the latter that it grants. Suruga's wish to be the fastest in her class masked her real wish, which was to injure her classmates, and the Rainy Devil possessed her in order to grant that.
This psychologization of wishes, and the introduction (under a different name) of the unconscious is an interesting development, particularly when it's done as an explicit replacement for the old "monkey's paw" type wish, where the malevolence is outsourced to an evil spirit twisting the good (if unwise) intent of the wisher. Jacobs' story was published two years after The Interpretation of Dreams and two years before The Psychopathology of Everyday Life, but it's a pre-Freudian tale.
Not of course that the older kind of wish-twisting has been definitively superseded. Even though psychologists might like to claim that any sufficiently analyzed action is indistinguishable from a subconscious wish, it would be an arrogant kind of solipsism to suppose that there are no other forces in this world than human minds. But Rainy Devil vs. Monkey's Paw does offer an interesting choice of ways to tell the story of a wish gone wrong.
So, turning (inevitably) to Madoka and that other wish-granting entity of dubious morality, Kyubey, on which side of the divide does he fall? He certainly has an ulterior motive in wanting to grant girls wishes, and everything he does is aimed (ultimately) at bringing them to despair, so he might seem to have an excellent incentive to make their wishes turn out badly, either through some wilful misinterpretation of their words or through granting their unspoken rather than their spoken wish.
Watching Bakemonogatari brings home to me just how strange it is that he does neither. The wishes he grants are granted "straight": Mami lives and becomes a very competent Magical Girl (the Monkey's Paw might have let her live but in excruciating pain from her injuries); Kyousuke is healed; Kyoko's father is listened to by his flock; Homura really does go back in time to protect Madoka; and Madoka does remake the universe. Of course, arguably all these wishes turn out badly, at least in part. Mami lives, but she is alone and tormented by loneliness; Sayaka heals Kyousuke but loses him to Hitomi; Kyoko's father is driven mad by the discovery of what she's done; Homura's attempts to save Madoka turn Madoka in a potentially world-destroying witch; and even Madoka's wish, while it works out just as she intended, means that she ceases to exist in this world.
Nevertheless, these wrong turnings (certainly the first three) can't be directly attributed to wilfulness on Kyubey's part: they are simply foolish wishes. Mami, in her agony, didn't think to wish that her parents should also be saved (a regret that's brought out more clearly in The Different Story manga). Kyoko's was a child's wish: she didn't have sufficient understanding of her father's vocation as a priest to guess how he would react to having a congregation gathered by magic rather than faith.
And then there's Sayaka: here of course we really do have a two-sided wish, and Mami highlights the issue in Episode 3: "Miki-san, do you really want to make his dream to come true? Or do you just want to be his benefactor? The two may sound the same, but they are actually completely different." Of course, it would be unfair to say that Sayaka says she wants to heal Kyousuke but she actually wants him to be grateful so that he'll become her boyfriend. She wants both: her love of his music and of him as a musician are not simply feigned because she wants him (this is made clear in her final appearance in Episode 12), and her compassion for his suffering is also perfectly genuine. This is why, despite acknowledging the truth of Mami's warning, she goes ahead and wishes anyway: her conscious mind has a convincing (because true) story to tell that effectively masks the subconscious motivations that also exist.
Nevertheless, none of this is arranged by Kyubey: he didn't throw Hitomi in Kyousuke's path; he didn't tip off Kyoko's dad; he didn't refuse to save Mami's parents; he didn't know about the side effects of Homura's wish. What he does understand, and has found that he can rely on, is that human beings lack self-knowledge, and that for this reason their wishes will inevitably betray them. And that, my friends, is one reason why Madoka is more like Shakespeare than W. W. Jacobs.