Round mirrors win when the room is architecturally angular — flat walls, rectangular furniture, squared bedheads, straight-line windows. Introducing one curved shape softens the whole room and gives the eye a natural focal point. The round mirror becomes the quiet hero: it pulls attention without shouting for it. Rectangles disappear into the geometry, which is sometimes what you want, but when a room needs a centrepiece, a round shape does the work. Common scenarios: above a console table in an entryway, on a bathroom wall between tiles and a rectangular vanity, in a powder room as the single decorative piece, or on a lounge wall as a sculptural anchor. Avoid round mirrors in rooms already full of curves (arched doorways, round dining tables, curved sofas) — you'll create visual noise.