This posts’ title is a quote from the Dead Alewives’ famous “Dungeons & Dragons” sketch. When I recently listened to the sketch again this line made me think. Usually when I run a game as GM I make sure I describe everything as meticulously as possible, especially when I want to set a special mood by this particular scene. But the Dead Alewives’ sketch reminded me that I often forget to describe what the player characters can smell (or even taste).
But smell can be a powerful tool in a GM’s arsenal (By the way, I advise against using smells as some kind of prop in gaming. Putting a piece of rotting flesh under the table will not set the mood but will probably make your players sick). But you should try to remember mentioning smells and sometimes even tastes in your descriptions. Smells are tied to emotions and memories like no other sense.
And as a GM you can use this fact to your advantage. In a scene where the players are operating in a modern day hospital mention the antiseptic smell. Or use the aforementioned smell of mildew (and other unpleasant odors) in underground dungeons. A bazaar will seem much more interesting if you describe all the exotic spices and how they smell. And if you remind your players that their characters have an olfactory sense, they will probably make more use of it, too. And this will add a lot to the atmosphere of your game in the long run.