One of the things I’ve noticed in my years as a GM is that my best games come from campaigns that revolve around something that I feel strongly about. No matter what emotion was involved, these games were made more memorable due to the fact that I had a strong emotional connection to them, and was generally able to translate that emotion into the game subconsciously. The effect, of course, was no less than dramatic as players were also caught up in the same emotional resonance and everyone had a memorable time.
I know that it sounds strange at first, and perhaps even nonsensical when you read it, but I firmly believe that the intensity of a GM’s enthusiasm and emotion translates to the game that they’re running. The most obvious way that this is shown is if a GM is not really interested in running a given game at all. If it feels like a chore to the GM, then it will definitely show to your players. Whether it’s from your tone of voice or body language, players will interpret your boredom and reflect it, resulting in a game that will feel flat for both parties.
For a more nuanced example, I once ran a World of Darkness campaign that started the players off as Mortals, before later on Awakening them to become Mages. The first part of the game was one where I was determined to make a strong horror impression on the group, and I brainstormed to the point of creeping myself out. I took the ideas that made me uncomfortable or kept me awake at night, and unleashed them on my players (after making sure that they were all aware of the campaign limits, of course) without holding back. Each character scenario was creepy and deeply disturbing, and even towards the tail end of the Mage Campaign, the players confess that those first few sessions were the most memorable (and traumatic.)
What matters is that the GM should feel a strong emotion towards a given theme or concept before he runs the game. Running a half-hearted game is going to consign the game to being mediocre at best, and as a GM, you owe yourself and your players more than that.
Take note however that Emotion in this case isn’t restricted to fear. I ran a very successful Superhero campaign based on the emotional theme of Righteousness. That theme covered the entire campaign, and players had to make tough choices for their characters because of it. The campaign also became a success because of it, as the players themselves were drawn into the drama of having to fight for what’s right, no matter how difficult it was to do so in a world that rewards pessimists and spits on ideals.
An interesting side note of course, is that negative emotions are also a powerful motivator for this sort of thing. For example, I feel very strongly about certain aspects of Changeling: the Lost and Demon: the Fallen. Both are fantastic and evocative games, but they deal with topics that I find deeply disturbing. I have no doubt that if I could ever get the time to tap into that uncomfortable part of myself and run with that aspect as theme for the campaign, I can make a very memorable campaign. Whether or not it will be “fun” however, is an entirely different question.
So the next time that you’re planning a game, take a moment to gauge how you feel about it. The stronger the emotion, the more color the end result will have. There’s more to running a game than just plot hooks and NPCs, after all.