There’s a certain ongoing tension in game design between what can be called “crunchy” (detailed and often complex) and “freeform” (simple and often vague) rules systems.
Interestingly, although some gamers say they want something simple and freeform, when it comes right down to it, they look for the certainty and reassurance of a system of clearly laid-out and detailed rules. The oft-asked question is, “How do you handle this situation in game-terms?”
Now, one of the good things about RPGs, in my opinion, is the unexpected. Things turn up in games you didn’t see coming and the GM and players need to adapt. It’s those twists and turns, the thinking and creating on your feet, that make RPGs fun to me, and differentiate them from pre-programmed computer games where your options are (necessarily) limited. Anything could happen in a tabletop RPG, assuming the Gamemaster and players let it.
Funny thing is, sometimes games get in their own way in that regard. When an unexpected situation arises, it sometimes paralyzes game-play for various reasons, most of which boil down to a tendency to over-analyze. Either an impromptu game-design discussion breaks out about how to extend the existing game rules to cover the situation or else an extended search through the existing rule book(s) for the rules that do cover the situation begins (sometimes ending with “wow, that rule is dumb”). Note that I’m not saying these are bad things or making a judgement; if you happen to enjoy impromptu game-design discussions, then it’s still fun, I’m just talking in terms of the flow of the game.
It’s especially interesting when you’re dealing with totally common-sense situations, where the solution in narrative terms is blindingly obvious, but because there isn’t a game system for it, a clear and defined ruling, things bog down. The desire to have or make a rule for that situation, and other situations as they arise, seems to contribute to the progressive accretion of rules to a system. Do you eventually reach a point where a game system can’t get out of its own way? Perhaps. I suspect it depends on whether or not you prefer to focus on the “game” aspect, wherein stories arise as a byproduct of describing what happened in the game in terms of a narrative, or the “story” aspect, in which some things happen “outside” of the rules system, but that doesn’t matter so long as it helps the narrative to flow.