One thing European architects and designers do well, in history and today, is consider the entire envelope. Not just walls and floors of an interior, but ceilings as well. Here in the states, so often we paint the ceiling white, stick a fixture up there (that hopefully isn't overly offensive) and install all manner of ductwork and fire equipment because 'no one ever looks up there'.
People do look up and a ceiling is as important as any other surface! I think these 3 images from my travels prove that point (in formal and ornate ways) - who could NOT notice these efforts? The first thing people tend to notice with memorable interior designers are their ceiling treatments: Real estate agents always will point out crown moldings and any decorative beams. It shows an attention to detail. Don't think no one will notice ill-placed air vents, sprinkler system heads or home depot light fixtures!
First image: Royal palace private apartments: Naples, Italy.Second: underside of archway in St. Germaine, Paris - at the end of the Pont Neuf.
Third: private palazzo entryway (under restoration) in Naples, Italy.
