To me it's a matter of being able to adapt rules to the specific situation. Over the last 2 editions my players have REALLY gotten used to the idea that the rules are set in stone, the DM isn't allowed to change them.
If a spell says "does 2d4 points of damage to a target creature" and a DM ruled that you could use it on a door, at least one of our players would get very angry. The rules say "target creature" and the DM was breaking the rules by ruling it worked on objects.
If the rules said "opening a door is a minor action" and the DM said "I'm going to say that if you are trying to do that with your hands full it will take your standard action for this round" SOMEONE would complain about how the DM was out to get them and wasn't following the rules properly.
Really strictly written rules get people into the mindset that the rules cover EVERYTHING and that anything the rules don't cover simply isn't allowed.
One time I decided to make up an NPC on the fly with about 10 seconds worth of notice. So, I made up an AC and some hitpoints and a bonus to hit and started combat. When the PCs found out his AC through trial and error one of them started doing the math and figured out that his AC was wrong by 1 point since I had guessed rather than calculated it. I tried to tell them that it was just a bonus from his skill. They asked me exactly what feat he had that provided that bonus and which book and page number it was on so they could look it up. When I eventually relented and said "I just made up his AC, it wasn't based on any rules at all. I just picked an AC that sounded like it would be challenging to you." Then the group said "Well, in that case, I hit it last round because its AC was one lower!" I tried to explain that even though I made it up, I didn't regret it and its AC was going to stay the same and I certainly wasn't going back multiple rounds to retroactively apply damage. My players were not happy about that. The rules were the rules and they needed to be followed precisely.
I prefer rules to be written a little bit more vaguely to allow for DM interpretations. I like them to be more vague to encourages players to be in a mindset of the rules being there to help imagine the story but the story determines the rules rather than the other way around.