The Mundane Milieu

Or An Oddity Too Much
I have read that C.S. Lewis (Narnia) had a dictum that to write about how odd things affected odd people was an oddity too much. Perhaps the same can be said for our gaming milieu. I have noticed a trend, starting with the WotC era, of player characters becoming more specialized, more unique, more customized and perhaps more odd. When played in a relatively mundane setting, the oddity factor centers on the PC. However, if such PCs are played in a truly "gonzo" setting where surprises are happening every encounter and nothing seems predictable do we have "an oddity too much"?
A mundane milieu can be useful when establishing a baseline for horror or to focus attention on the singularly unusual feature in a setting. The surprise factor in horror is a big part of making the bad stuff "horrible". Once the monster is revealed in detail, much of the suspense is gone whether we are talking film, literature or game. A mundane setting and mundane characters make the monster stand out and any supernatural powers it possesses that much more unusual and difficult to deal with. The mundane setting may offer few powerful resources for dealing with such "horrible creatures" and therefore require creative, out-of-the-box thinking on the part of the players. 
Mundane characters are ones that fit nicely into the milieu. They are characters much like people in our own world, except fictional. They have skills that may be above average, well above average in some cases, or even abilities that seem supernatural such as the ability to cast a magic spell or two. The more one plays the game, however, the less "magical" those spells become if over-used. At low levels even Magic Users and Clerics seem more mundane than many of the monsters they encounter. Once players become familiar with the tropes of the game, it is only at higher levels that casters appear truly "odd" in the power of their abilities. 
Balancing the game is an art, as is achieving a desired feeling or atmosphere in a game session. Sometimes overwhelming player senses with a barrage of the weird and unexpected, so as to achieve disorientation or wonder, is exactly what is desired. More often the referee will attempt to present a believable, predictable world where things mostly work as they do in real life, so that players can use their general knowledge to assist them in thinking of creative ways to deal with various in-game problems as presented by the referee. Then, when something odd happens in-game, it stands out and creates a sense of wonder and surprise, if not out-right shock! 
Odd player characters often end up shaping the in-game action into an exercise in watching their oddness unfold...in other words, it becomes all about their own oddities. One odd PC assumes center stage while the other players watch and two odd PCs both "acting out" frequently battle for the spotlight. A group of odd PCs and their players may alternate turns show-casing their PC's oddities, and that then becomes the story collectively created at the game table. 
Mundane characters allow the odd nature of something they encounter to become the center of the story. How the PCs deal with this unusual "thing" becomes the central event as remembered and retold over and over. Those are the stories that C.S. Lewis and other authors describe in their writing and they may be the stories you want to pursue in your gaming.