Robert Genn
"Staffage" is a historical term for placing people and animals into landscapes. Like many time-worn conventions, there's more to it than meets the eye.
The populating of pictures--mainly views, architectural subjects, natural wonders and other general scenes--was once more widespread than it is now. In the 17th century, some Dutch painters actually employed other artists to put people in. Staffage was used as an aid to composition, a device to show scale, and an opportunity to enliven scenes. Figures were strategically placed, often holding a stick, cane, spear or gun, sometimes together with a lesser person, or a dog or other beast, or even pointing toward the picture's center of interest. Sometimes a jacket or coat brought a bit of colour to a sombre landscape. The Impressionists gave themselves a choice--some went for it, others didn't. These days some photographers dine out on girls in red shorts on foreground rocks. In current landscape painting, Nature is more likely to be unpopulated. This, of course, will change.

Many painters these days don't do figures because they can't. Actually, this was always true. People are a tough order. But there's more to it than that. With the rise of rugged individualism and the concept of "me first," it is often the viewer who feels the need to supply his own figure. Living in someone else's world is not our style anymore. It's not the wealthy lord in the big hat who gazes at the Sphinx, it's us. The wonders of Egypt are now theoretically available to all. The idea of other people enjoying the architecture in Piazza San Marcos in Venice is more the business of illustration. With the widespread suspicion of sentiment, anecdote itself has become distrusted and even suppressed.
Next time you think about putting in a figure or figures, think about what may be pulling you around. Early this morning I painted a tranquil lake in the Western Canadian foothills. I couldn't prevent myself from putting a couple of guys and a dog out there in a yellow rowboat. The devil made me do it. I'm not sure if I made the painting better or worse. What do you think? To me it looks curiously old fashioned. We put the painting at the top of the current clickback so you can shoot it down if you feel like it. 
Best regards,
PS: "I'm done with girls on rocks." (Maxfield Parrish, 1950)
Esoterica: I know it's a bit to ask of many artists, but I'm a believer in understanding your "genre," even for the sake of breaking the rules. Genre means your kind or art, your style, your times. At first, the human body was the only subject matter worthy of paint. When the grand landscape showed up, figures, clothed and not, were reduced to accessories. Then the figure came back into prominence and was the main subject once more. These days, a lot of effort is given to the spirit of Nature, bereft of mankind and even the hand of man. Some sort of longing or wish, I'm thinking. Niagara Falls is her own subject again. A few more years and once more it'll be the little guy going over her in a barrel.