But the reason I include a Gorechainn devil in an encounter is because I want to use it to force the PCs' stories to change - eg from attacking their enemies to attacking their friends. If I don't want that I don't use the creaturre, or I rewrite it.Effects that come from the in-fiction opposition--things like being charmed or paralyzed or petrified or dominated or frightened (I know that's a negative condition in 3.x and 5E, don't know about 4E) or whatever, coming from what my character in the fiction is encountering in the fiction, such as a harpy or a gorgon or an illithid or a dragon--do not bother me at all. They are happening to my in-fiction character in the fiction, because of other things in the fiction that are behaving according to their natures as established in the fiction.
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Effects that come from around the table--whether they come from the GM or another player--things like Compels in Fate, or the strings or whatever in Monsterhearts, or IIRC the various ways Stress is applied to characters by the GM in Blades in the Dark--bother the heck out of me, because though they represent things in the fiction (I'm clear on that, really) they aren't emerging naturally from the events in-fiction; they're emerging because someone else around the table has decided to use them to force my character's story to change.
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Whatever effect is being placed onto my character by GM as GM (not as opposition) or fellow player (not as character) by metagame mechanics does not feel to me as though it is emerging naturally from the events preceding it; it feels as though a gun is appearing onstage during the third act.
And in the compel case, if it's what Fate Core calls a decision compel (pp 73, 211) then the GM is playing that non-rational or habitual or compulsive aspect of the PCs' personality, making it active in the players' decision-making process and thus giving life to it at the table. As I've said I don't play Fate, but when GMing D&D 4e or Prince Valiant I will play the devil on the shoulder, and offer players bonus resolution dice for commitment/morale if they take particular actions.
What is key to making that work is that the players are confident that whatever choice they make - eg to take the compel or to decline it - the game will go on. For that reason I find your discussion of taking compels and accruing Fate points, which is expressed in the language of a serious boardgamer or wargamer, a bit curious. I fully agree that the Fate point economy won't work in a game that plays like a classic D&D module (eg White Plume Mountain) but I don't think that's how Fate was designed to be played.
An event compelt (pp 72, 211) is similar - the GM is trading on PC backstory/reputation to introduce complication into the unfolding narrative. The player can pay to buy off the complication, or can take a point and suck it up. The complication arises from the fiction - the PC's own past - and the GM is doing what s/he normally does in a trad(ish) RPG, which is drawing on all that established backstory to frame things.
I think there would be an interesting question in a Fate game about how to play out events-based compels, but to me it doesn't seem that hard to do it at the level of the fiction. Eg looking at two examples on p 72:
Cynere has Infamous Girl with Sword . . . so it makes sense that, unfortunately, an admirer would recognise her in the stands and make a huge fuss, turning all eyes in the arena her way
As the GM starts narrating this, the player spends a Fate point and says "I pull my hood up over my face before the admirer can get a really good look" and the tne GM - understanding the mechanical significance of what has happened - narrates "The admirer sits down, not sure that it was Cyrnere after all.:
Landon has I Owe Old Finn Everything . . . so it makes sense that, unfortunately, Old Finn was captured and taken far into the mountans . . .
As the GM starts narrating the NPCs telling Landon how Old FInn was captured, Landon's player hands the GM a Fate point while saying, in character, "Are you sure you didn't make a mistake? Finn has to be OK!" And then the GM, again understanding the significance of the Fate point, narrates something like "At that moment Old Finn walks towards you. It looks like he was out picking mushrooms in the forest. 'Nah, that weren't me what was captured. You musta got half-a-look at some other white-haired fella!'
Obviously what I'm suggesting here wouldn't be the only way to handle the refusal of event compels, but it seems fairly straightforward as one way to do it.
And if these aspects of the character are experienced as rabbits from hats, or third-act-only guns, or whatever - then that suggests to me a bigger issue, that the players haven't chosen aspects that they want to play, or that the GM is not incorporating the chosen aspects into play. A similar thing can happen with Beliefs and Instincts in Burning Wheel - the rule books and commentary texts give advice on how to fix this. I assume that similar play advice exists for Fate.