For practical and aesthetic reasons, not all of the furniture in your home should be placed against the walls. Putting all of the furniture against the walls restricts how you can use a space and can mean that people trying to talk to each other find themselves at uncomfortable distances. So put something solid behind seats that “float” in the middle of a room, because their backs are more than a couple of feet from walls. You have a range of options for that “protective” element, but the key is to keep any of those hypothetical rear-approaching evildoers about an arm’s length away—a credenza behind a couch does that. Try to place your furniture so that as few seated people as possible have their backs to hallways or walkways.
Things move in nature, but when something moves inside most of the places we design, generally, it’s on its way to crashing to the floor. A mobile, wall hanging, or window curtain that drifts in a gentle air-conditioning or heating current near the ceiling adds comforting motion to a space; it’s reminiscent of breezes moving through long-ago meadows on wonderful sunny days. If the air-conditioning or heating currents in your home make you think more of hurricanes than drifting butterflies, reposition mobiles or flex sculptures etc. so they move in a window draft or the current of air behind someone walking through an area instead. Daylight in a space will naturally create a sense of movement as shadows change position during the day.