Last Thursday's game didn't go so well. What felt like easily 2/3 of the time was spent looking at each other and saying "well do you have an idea for a scene? I can't think of a conflict!" Upon reflection I'm certain we were breaking the rules and fairly certain that's what caused the play breakdown.
Here's how it's supposed to work, as far as I can tell: a player requests a scene which may or may not have a known general agenda ("here Dr. Mere is going to argue with Colonel Hike about a fair trial for the corrupt planetary governor", "all right this is the volcano eruption scene!", etc.) but which has a known starting point, enough for the Producer to frame the scene. Then there is freeform play for a bit until someone calls for a conflict, at which point stakes about how the characters are affected need to be set.
The goal is that the great majority of scenes culminate in a conflict. But this is a symptom of good play, not a cause, and trying to short-circuit the process and think of your awesome conflict before the scene starts, every scene, causes a breakdown in play. Proof: last Thursday.