The PC party had to go to the goblin market to learn the secret weakness of an aspect of one of the true fae they have to oppose. This is always a risk, the goblin market deals with trading 'anything for anything' more or less. They were given the rules going in, and things started out okay.
Until the PCs found the slave market. There were some significant people up for sale -- Lost, Atlanteans, a few other races from the past, and a Legendary Hero. The PCs were interested (the mage in the party was curious about the Atlanteans, and the Sin Eater was interested in the Atlantean or a Lost). They learned that the price for these was steep. ' Wisdom' for an Atlantean (one knowledge skill drops to 0 ... and you're never able to buy it back up).
See, the rule for me in the goblin market is that when you buy something, you pay XP. Not out of your XP pool, but out of something roughly equal. So, buying an N/A level advantage costs essentially a 'key skill'. Reasonably fair.
Well, one PC decides he wants to buy the Legendary Hero. He's told that a 'heroic event' from his past would be the price. He (wrongfully) thinks that a specific memory he has (where he decided to plunge into a dangerous region by himself for no good reason, then battled some horror under there) would be suitable. Instead, I chose the most heroic event the character had done (driving a car madly in the middle of the night, avoiding an enemy truck trying to run them off the road, pulling a wagon full of rescued people, through an umbral realm, towards reality). With this, he lost his Drive skill -- permanently.
The player didn't take this well. At all. He said that the character's driving skill was essential to the character. I acknowledged this, but that was the most appropriate skill to be taken. Of course, the PCs being in the goblin market, anything's up for negotiation. But... he folded up his laptop and stopped there.
The rest of the group carried on, going through their errands, making contracts and negotiating for things. Eventually, the mage talks to an oath-breaker. He had a pact with a demon which was going to get him killed, and he negotiated to have it nullified. The result -- the benefit of the contract is also broken (meaning that the PCs are now wanted fugitives in the city). The mage also negotiates so that the other PC can have his memory (and thus, skill) back. This gets discussed, and in exchange, the mage takes on the contract -- Fate (the thing the mage uses all the time) is turned against him. He is now going to be victim to 30 Dramatic Failures over the rest of the game.
The rest of the players seem fine with the session and how it played out. Everyone paid a price (the Lost in the party gave up a 3-dot relic, a point of Clarity, a permanent point of Empathy, and the memories of her friendship to her Fetch and the love and acceptance of her grandmother). The guy who lost his drive skill was quiet through the rest of the session, and didn't say 'boo' even when leaving.
The player who drove him home contacted me and told me the other guy won't be coming back to the game. Eh. I'm willing to accept this.
(For those keeping score, this was that guy ... the one I used to have huge discussions about morality with'.)