Hi, all. I just thought I'd let people know that this entire thread has been very helpful for me, in figuring out why my players are playing the way they are. We're playing a Serenity game, where players get "Plot Points" and can spend them on different things, including changing the world (with the GM's approval and probable twists.) Most of my players are only spending these points on enhancing their die rolls (even though there is not that much rolling per session).
I asked them about this. They couldn't express their reluctance to use them. I offered my own opinion (the following is probably highly paraphrased):
Me: "I know for me, when I'm playing, a large part of the fun is discovering the world, and adding things myself negates that."
Player1: "Yeah, I do enjoy the challenge, using what's there to construct a solution to the challenge at hand, like my character would."
Some of the other players just kept forgetting they could use the points to influence the world, however. These tend to be the players who play a character with certain characteristics no matter the game. I think letting the GM twist whatever a player comes up (or outright veto it) is the best balance I've seen in play. And by using up a resource, not everyone is throwing around descriptions and items all the time.
As a player, however, I really agree with ExploderWizard. If I'm doing something to influence the game world, my character should be able to explain it later when recounting her heroic adventures.