One of the strengths of PSF is that it skips over the unimportant details to get to the next good scene. I'm interested in how people determine what are the unimportant details, and which are the good scenes. Obviously this varies from table to table, but how do tables go about getting that consensus?
I don't think it gets determined in that way-- cut out the "bad scenes" and go straight to the "good scenes"... but rather, players just use standard improvisational theater technique: the Offer and the Accept.
The start of any scene of improvisation uses the "offer" and the "accept". One performer offers something into the scene-- makes a declaration of some sort of something going on or being felt or being seen or whatever... and the second performer accepts that what was offered is true and acknowledges the fact. The second performer then offers an additional detail to the first person's offer of what is happening in the scene, and then the first person accepts that bit as now being factually true to what is going on. It's your prototypical 'Yes, And' situation.
What I think is happening during PFA is that the performers involved (the DM and the players) MAKE that zoomed-in scene important by one person offering something and the others accepting it and then adding to it in such a way that the scene BECOMES important. It's not that bad scenes are skipped, it's that every scene IS MADE good by strong and important offers, strong accepts, and then even stronger counter-offers.
If the DM narrates the party has left a dungeon, he might make an Offer that the city is less than two miles away. The party then Accepts that to be true, and then Offers that they are going to go to that city and find someone to buy all the treasure they found. They've 'Yes, Anded'. The DM Accepts what they have said, and then makes an Offer that two hours later, the party finds themselves outside a blacksmith shop. The party Accepts that they have traveled the two hours and are outside the smith, and then Offers to make Streetwise checks to see if they perhaps know anything about the blacksmith himself. The DM Accepts the offer of Streetwise checks, has them roll (after setting an internal DC), and then depending on the result perhaps Offers that the party has heard this smith deals with the black market.
Now all of a sudden, we've moved our scene focus straight from exiting the dungeon directly into a scene involving a crooked blacksmith. Did the group "skip" unimportant scenes along the way? No. Reason why? Because no one treats these Offers made AS unimportant. Every Offer made is treated as a vital part of the story. Even if someone by some chance had made an Offer that seemed unimportant... the other players would
turn it into something important based upon their Acceptance of what has happened and the Offer of what happens next. And this happens instinctually.
For example, if in the example above... after the party made the Offer that they were heading back to town... the DM accepted it and then made the Offer that halfway on the journey back, one of the wheels on their cart broke. Why? No idea, the DM just threw the Offer out there to see how the party would react. And what would that reaction be? Mostly likely... the party would get out of the cart, and make the Offer that they will inspect the wheel, check to see what caused the break, and keep their eyes peeled for anyone or anything that might be spying on them. Voila! Their natural reaction to this scene Offering has now set them on a path where this scene will now be Important. Because the DM (if he's worth his salt) will naturally Accept that they are expecting an ambush, and then make an Offer in direct reaction to that (probably by actually having it BE an ambush.)
Now you might make the case that after the party checked out the wheel, and kept their eyes peeled for an ambush, the DM could make the Offer that nothing else happens, they fix their cart, and they make it back to the city. And thus, this scene in the road remains "unimportant". And yet... I would still claim otherwise. Even if nothing has happened per se (other than the wheel breaking)... just the scenes very existence has generated thought in the player's minds. Did the wheel really just break on its own? Did it not? Why would we even have this scene in the road if it did? What is the scene's purpose?
And thus... as these thoughts run through the minds of the players, they will affect future Offers they make. Maybe next time they keep more of a watch on the road for potholes? Maybe they choose not to take a cart next time? Or whatever they Offer to the DM in the future. That scene... while seemingly "unimportant" in the grand narrative of the campaign... has become important in terms of how the players and DM make Offers and Accepts in the future to direct those scenes in new and different ways.
And that's how actual improvisation works.