Hmmm, more vocabulary variations...
"Friction", that is, unfriendly vibrations between SG and Players is not a good thing ever. I think the above discussion centered more around cooperation and coordination of play-style. I think, all variables considered, the most important thing for a successful RPG is that all the players share the same play-style, be that one end or another of any spectrum you care to name. Any one player or SG could have other styles they enjoy as well, but unless everyone is on the same page, there will be friction, and less fun all around (sometimes even collapsing the game.)
Many players/GM's seem to not understand this, and keep one player around because they are "cool", even tho', unfortunately, they just aren't right for that particular game group, and the game suffers or dies because of it. Same with a new GM who tries to force their own style on the group- if the group doesn't like it, even the "best" GM and Game will fail miserably.
The rhythm of what plots to spin, what challenges to present and when, how to incorporate the Players' "what ifs" into the flow of the adventure, that is the question we're kicking around here. Not that any one person can give a universal solution, but just to be aware of it can avoid or solve the problems it can otherwise create.
However, the "friction" of unexpected challenges, of the SG not letting the players just waltz in and have their way with things, that is critical, and finding a balance between challenge and success, between the threat of failure and player-abuse, is a delicate art. I've had players who trust me to run a fair game, and they work to think their way thru the challenges I present- I've presented others with the same challenges, who are used to GM's abusing them, and they give up immediately, crying "How can we succeed against such odds?"
So, that sort of "friction" is often a matter of perception as well, and often a self-fulfilling prophecy- that is, if you think your SG is being unfair, then you'll fail, but if you have faith and persevere, then you'll succeed. Huh, just like in RL, kinda.
