It's great when the dice help decide the story.
Last night's Dragon Warriors game went really well - there had been a couple of hiccups with the last session, what with a bit of difficulty I had with player attention (but that was no fault of mine) - but last night was good. The players are trying to find a way back home and their investigations have led them to Ereworn. They're trying to find a legendary lost city in the mountains where, they hope, they will find the means to return to England.
First, however, they needed to find a map that they have heard might lead them to the city, but this was in an old Dwarven mine that was overrun by goblins and giant man-rats (basically exactly the same as rat-ogres from Warhammer Fantasy). The idea was to sneak into the mine and steal the map.
That's when things went a little awry. The manrat was chained to a hobgoblin, who was obviously it's keeper, and it appeared to be manic, straining at the leash and trying to get away to feed on a corpse in a great hall where a sacrifice had just taken place. The players felt that if they killed the handler then the manrat might go out of control, creating a diversion they needed to get past the other hobgoblins without the need to fight. So, they aim with two crossbows and a bow and they all unleash their missiles at the handler. They all hit but not one of them pass the Armour Bypass roll. The arrows bounce.
Of course, the hobgoblin turns, sees these three men looking somewhat shocked, and unleashes the manrat on them. The party consists of a Rank 2 Sorcerer, a Rank 2 Knight and a Rank 2 Assassin. The manrat was Rank 7. What followed was a 30-minute combat as the players wore the thing down.
The dice really conducted the flow of the encounter. Fumbles occured just when the players didn't want them to which added extra tension, a critical occured just when they needed it and won the day, which resulted in lots of cheering, high-fives and handshakes. After the encounter several random rolls came up trumps for the players when they finally located the treasure room and the map (a +1 sword for the Sorcerer, a set of +1 plate armour for the Knight and ten +1 quarrels for the Assassin, plus some random potions). On top of all this they all advanced to Rank 3.
As far as the flow of a story is concerned I'm all for GM input as they are the ones who control the environment and the advancement of the story, but when the situation calls for dice rolls then I like to let the dice talk. I'm not a great fan of GM fiat or obvious fudges as that gives the GM too much power at the table and takes away not only the illusion of free will but also the randomness of the dice roll. Players won't enjoy the game if they feel that they are not in control of anything during the game and may also feel that their dice rolls are pointless.
You can't rely on dice rolls to make every encounter better but when the dice roll well, especially at just the right moment, it adds a level of enjoyment and accomplishment to the game that everyone can appreciate.