So, a few weeks ago, and throughout this blog, I've said numerous times to talk about what kind of game you want to play with your players first. Today, I have a quick story about what can happen when you don't do this. This story is second hand, and I haven't confirmed its authenticity, but I also have no reason to doubt the source and it sounds plausible.
So a friend of mine is in a Table Top group, and they were switching games when the GM got a hold of Dark Heresy (if you haven't tried it, I really recommend it). Now, the other players weren't too keen on Dark Heresy, they wanted something a bit lighter than the 40k Universe lends itself to, but the GM was insistent and so they played along. So the game goes on and they make some characters. They end up with 3 guys and 2 girls, some scum, an arbiter, a tech priest, the general spread.
Now, the players are having fun, and giggling here and there in the game but the GM doesn't pick up on anything being afoot. The adventure continues, until at last they capture the old psyker witch that has been causing problems in the hablock. At which point the PCs spend several hours trying to figure out how to remove the mask and reveal that the old psyker witch is actually the rival inquisitor just trying to keep himself in a job. Suddenly the GM realized what had happened.
See, the players didn't want to play Dark Heresy, as I said they wanted something a bit lighter. So when 'forced' into Dark Heresy (The GM wouldn't budge) they took matters into their own hands. Turning the dark, grim, and gritty 40k universe, into a venue for Scooby Doo. Each player took up the role of one member of the Scooby Gang, and just played along while keeping to their character inspiration. Hence the giggling, hence the running. The GM, as said, never realized until they tried to unmask the witch.
Now, this can be fun and amusing, but the GM was understandably a little miffed. Just like the players had been when left with the choice of something they weren't 100% keen on or no game at all. Hopefully everyone learned a valuable lesson!