Here's what I mean:
(cw for violence against teenagers)
One time I was playing Apocalypse World with my partner, and this shitty teenager was going to rat my character out to a gang of fascists in the community for raiding the liquor stores at night with a friend. It wasn't a moment of indecision, where we had to reach to the game for support. This was an active decision, where I picked a move of my own volition for some perceived benefit. I threatened the kid with my crossbow to try to get him to back down, but nah, he was a shitty teenager pumped up with his own sense of importance and invulnerability so he wouldn't back down, and because I was going aggro neither could I. I couldn't bear to kill him so I shot him in the leg and bolted.
(end of cw)
I, me personally, regretted the hell out of that decision. After the end of that session we haven't played in that campaign since.
From some distanced narrative perspective that I can acknowledge but not fully inhabit, I know that that was a powerful moment, that it had moved the game forward somewhere new and interesting, that it was a profound statement on the nature of violence and my regret was in that sense justified. I know that I most definitely had not been locked out of play, and none of my powers as a player to act on the conversation had been diminished, but all the same I was no longer willing and eager to roll the dice.
Now, we could totally go back and retcon that event, but for some reason we haven't done that. Some sense of fidelity to the fiction and the rules prevents us.
I'm sharing this story because I want to try and figure out whether there are different kinds of regrets, and whether the kind of regret that Vincent is talking about is the same as this kind of regret. Either way, the implications are really interesting to me!
If it's the same kind of regret, then we have more information about what it means when we say "regret" making a contribution, and what it means we we talk about positively asserting your idea in the conversation. Maybe we can consider more closely how to separate conversational benefit from a player's emotional attachment to fictional outcomes.
If it's a different kind of regret, then we could perhaps consider the possibility that when a player reaches opportunistically for the rules with an idea they want to bring to the conversation that it might be a bad idea, and when the game affirms that idea as a positive and active contribution to the conversation they might come out bruised and unhappy. How the heck do we deal with that?
(A third possibility I see is that you can design rules that are supposed to sting and when they do, that's the point! And yknow, fair.)