As a DM you have an arsenal of weapons to attack any of the problems that come up during your game. But, what most DMs don’t realize is that the greatest weapon they have is one simple word: no.
That’s not to say you should tell your players no all the time and turn you game into an exercise in tyranny. It’s just I’ve noticed many DMs who are too willing to let their players get away with anything they want. Too many players these days feel like they’re being ‘railroaded’ because they always get to run into the tavern, completely away from the adventure and kill everyone. They feel like the story isn’t about their characters because they aren’t the center of every NPCs attention at all times. They feel it isn’t fair when their character gets bloodied. Why could this be?
I guess a lot of DMs are just afraid of telling their players who’s in charge at the table. The ongoing campaign isn’t just your story, never forget that. At the table you’re creating a narrative together. And anything that disrupts that narrative is anathema to what you’re trying to accomplish. I’m not saying you have to force the players into the castle when they want to go the forest, but if they want to moon the king and act stupid to the townsfolk, that’s unacceptable (and you might want to rethink members of your group). When that player says ‘I drop my pants’ you tell him no, you don’t. With that one word, you remind the players who is in charge, you remind them of the tone of your game, and you do it all without having to get snotty or hurt feelings.
But, this must be used responsibly. A player wants to pick a game breaking option he found in the bowels of the internet? Say no. A player wants to start killing party members because ‘that’s what his character would do’, you tell them no. But if a player wants to do something interesting, something that won’t ruin the game for everyone else, you let it happen. The best times in this game come from the unexpected. Remember, you’re all in this together. It’s not about you; it’s about everyone at the table.