Original Position Fallacy

Mrs. Asimov: How pleasant it would be if only we lived a hundred years ago when it was easy to get servants.

Isaac Asimov: It would be horrible... We'd be the servants.

—Conversation said to have taken place at some social function

When making up his mind about a social system (laws, taboos, customs, whatever), Bob is likely to be biased by where he expects himself to be placed in this system.

Of course, his daydreams are likely to turn into nightmares as he gets to know what it's really like on the other side and he already made a moral commitment to principles that are now to his disadvantage. He would have been wise to think in the same way as John Rawls' thought experiment about the "original position". But now it's too late for that. Bob has already painted himself into a corner. If another character actively manipulated him to get there, this can be called an Original Position Gambit.

A character doing the Original Position Fallacy may start out as a Hell Seeker, end up as a Boomerang Bigot or both. If someone pulled the gambit version on him, it was probably a Magnificent Bastard skilled in Gambit Speed Chess.

Examples of Original Position Fallacy include:

Anime and Manga

In Fullmetal Alchemist, both the Emperor of Xerxes and the military leadership of Amestris fall victim to this. They both conspire with Father, the original Homunculus, to commit mass human sacrifice in order to achieve immortality; none of them realize that their immortality will consist of having their souls transmuted into a Philosopher's Stone.

Comic Books

In Chick Tracts, one of the most common types of Straw Loser is the guy who isn't afraid of hell. One variant of this is that he believes that hell exists and that it is a horrible place for the damned, but also believes that he'll be one of Satan's demons reigning in hell. Of course, his fate invariably turns out to be much crueler. (The two other main variants are those who don't believe that hell exists and those who think that it's not such a bad place.)

Literature

In one of the stories of Ooka Tadasuke, a famous Japanese judge of the 18th century, he has to divide a father's estate between twin sons. One is known as greedy and selfish; the other is known as having helped the father and for being honorable. No one can tell which son is which. Ooka picks one son at random and tells him to divide the estate. The chosen son starts giving himself all the money and property; and gives his brother merely the good will of the neighbors. The crowd thinks Ooka made a huge mistake until Ooka announces that he told the son to divide the estate, but that only Ooka has the power to award the items. Ooka gives the money to the honorable son and tells the greedy son that he needs the neighbors' good will more.
In the first novel of the Slave World series, the heroine is horrified with how naively her colleagues embrace the Alternate Timeline world they have found. The scientists join the society, believing that they will get to be part of the aristocracy and thus accept the social order where the aristocrats have absolute power over everyone else. And yes, they do end up enslaved.
- Zigzagged in the third novel, as Sarah seems to be falling in the same trap as her predecessors. She's actually setting herself up for permanent enslavement, although her plan is to belong to the woman she loves... Who then gives her the basic "thanks but no thanks" and auctions her off to a random aristocrat... a young lady to grow to become the true love of her life.
Debated in the book SS-GB by Len Deighton. SS Standartenfuhrer Oskar Huth states that when he figured out that the Nazi party was going to be in power, he decided that the only position that was acceptable to him was in the ruling class. Strength determined your status in Nazi life and he was going to be on top, regardless of the cost.
Invoked in one of Isaac Asimov's essays, quoting a dialogue at a social function. See page quote above.
Discussed in Colonel Butler's Wolf by Anthony Price. Butler compares himself to one of his more liberal-minded colleagues, noting that the colleague makes the usual error of believing he'd have been one of the masters in the old days but prefers modern society anyway, while Butler himself thinks the old ways were better even though he knows perfectly well he'd have been one of the servants.
A short story, in an anthology compiled by Isaac Asimov, in which a young man, obsessed with sex, finds a magical text that will allow him to assume the job of feeding dragons, aware that dragons' favorite food is young virgins. It turns out that the young man is actually a virgin, and that he is not serving food for the dragon, he is serving as food for the dragon.

Tabletop Games

In Book of the Dead, a book for the New World of Darkness (mostly Geist: The Sin Eaters and Mage: The Awakening), all the underworld realms presented are designed so the gamemaster can play them this way. It's outright encouraged in general, and one of the realms is designed so it's hard to NOT play it this way. This realm is called Oppia, and is a place of abundant soul-energy in the form of delicious food. The rulers are very generous and hospitable, and their rules seem simple enough. Sure the system runs on enslavement of souls, but those idiots are bad guests who broke the rules. Seems easy enough to accept... until you realize how very easy it actually is to break the rules. Including by accident.
In Dungeons & Dragons, this is a common ploy of the Lawful Evil alignment, inviting people to join a system that benefit the strong at the expense of the weak. The regular adherent is an Asshole Victim who overestimated his strength and is really unhappy with finding himself as one of the despised and exploited weaklings.
- It's mentioned in Fiendish Codex II that this is why Lawful Evil characters often make deals with devils - they expect to swiftly take positions of power and prestige in the diabolic hierarchy after their deaths. "No tyrant looks upon a wretched lemure and thinks that this will be their afterlife."
In the Mutant Chronicles book Ilian, there are two short-stories on this theme. Humans who joined the cult of Ilian because they wanted to become the exploiters rather then the exploited. And of course, their futures are so bright, since Ilian will smile upon them forever... until they fail or get backstabbed by each other, that is. Suckers.
Warhammer 40,000 and Warhammer Fantasy Battles: Many people who join Chaos cults do so in the hopes of attracting their chosen god's favor. Unfortunately for them, said gods are just as likely to ignore them, give them what they want or subject them to horrible (or benign) mutations.

Theater

In Shakespeare's Henry V, a trio of nobles are secretly plotting against Henry when Henry brings another traitor in front of them, asking whether he should execute or show mercy. All three say he should execute, at which time Henry reveals that he knows about their treachery and sends them off to be executed.

Other

This is what's behind the "cut and choose" method of sharing treats. Typically, when two children are sharing a cookie or cupcake or something like that, one child divides the treat into two portions, but the other child gets to pick which portion he/she wants.
Many historical revolutions that led to unjust systems or brutal dictatorships were supported by people who honestly believed they would improve their situation by helping the cause only to be even worse off at the end, or in the case of those close to the new ruler who hoped to rule with them, executed or imprisoned for life on trumped-up charges. The Russian Revolution is a textbook example.