I think it's a pretty well know fact here that traditional RPGs usually don't have stated and properly expressed player goals or win conditions. This is why they are considered by many to be not 'games' but 'toys'.
Since Forge we are getting better at this, so RPGs and Story Games could be more 'gamey' now. They are more 'complete', less 'flexible' than D&D. Examples: http://lumpley.com/index.php/anyway/thread/805
When someone tells us that (s)he didnt enjoy a particular well known favourite RPG, the standard accusation of 'you were playing it wrong!' is common and usually wrong because it blames only the player.
What is just realized is that if you are new to D&D and try to learn it, even if you don't really know how to do it, it's possible that you will have (some kind of weird) fun. Do you remember your old days playing a muchkin as a kid trying to understand the rulebook? Also, if you already mastered D&D, you can play it in a lot of different ways, and it's still fun. It's because of it's 'toyness'.
But when you play Fiasco the first time, and you are an experienced roleplayer, you have to use very different skills (improv attitudes and techniques), and also, if you try to play the game different than the rules and guidlines imply, there's a bigger change that it's gonna suck. Games are more 'rigid' so to speak than toys, so they break easier.
So maybe 'playing it wrong' is a real danger considering a small part of RPGs.
It's just an argument and maybe I'm not right but I feel that I'm into somethings. What do you think?