In my third year of college I was refereeing Fantasy Hero. It was one of my first campaigns that wasn't AD&D. Like all my fantasy campaigns it was set in the Wilderlands. This time it was in Viridstan the largest city.
For various reasons the players were being chased by the guards and the secret police, the Black Adders. The party split and one group turned a corner and ran down a blind alley. They asked "Hey Rob! Are there any doors?" I looked at the map and said "No Doors". The small group then asked "I know I go through a window!". I said "No windows either.". One of the players sighed "Come on Rob, there are windows you are messing with us.". I said "Look I understand, but on this map I have, they are all marked." I whipped out the map and showed them the symbol for window and the symbol for doors. And sure enough they were not any in that particular alley. The players groaned and awaited the arrival of the guards knowing their luck has turned.
Now was the story about them being captured by the guards? No. What it about them being NOT captured by the guards. No. There wasn't any story save the one that resulted from describing what they did.
Now did it suck being bagged by the Black Adders. It sure did. So what happened in Viridstan.
This unfortunate turn of events changed the course of the campaign. The other groups of players managed to escape leaving two in the hands of the Black Adders. I ran the next session in two halves. The first half involved the two being interrogated by the Black Adders. Now I had a lot of choices to handle this. I fleshed out some prisoners including some with good information they could use later. They did a good job and found out from one of them how to gain entrance into the palace itself. Then the second half involved the rest of the players plotting to bust them out.
In the end they busted the two out. Not only they busted the two out. They used the knowledge that was gained to killed the people running Viridstan and ignite a revolution. When that was finished they found themselves in control of the largest city of the Viridstan.
Now this wasn't what the campaign was about. I didn't plan this nor even considered it a possibility. They were in Viridstan to do research on finding the entrance to the Abyss.
The campaign was about putting the Ebony Crystal back in a ward field surrounding the Abyss to seal off a passageway used by Demons.
If I did what story gamers wanted there would have been a window in that alleyway because the players would have put one there. But in doing so the chain of events that lead them to become Overlords of Viridstan would have never come to pass. Nor they would have the elation and satisfaction of doing so.
It not about control. It about seeing players immersed in my setting and refereeing all the fun and crazy things they come up with. This is one of the reason why I call what I do Sandbox Gaming.