I'm always looking around at other people's home theatre/cinema setups on YouTube – looking for ideas, comparing, and just out of plain curiosity. One thing I keep seeing, though, is projectors set up in rooms with white ceilings, light carpets, white seating, white posters on the walls, all of the above. I've steadily been through the process of removing/replacing every light coloured object in my dedicated room over the last year, and the difference in available contrast is frankly staggering. And yet, you see these (sometimes extremely expensive) set-ups with light walls/carpet/ceiling/objects cranking their potential contrast ratio downward by magnitudes. It irritates me. Not least because often the people who built it or who own it will mention their extremely expensive projector's excellent contrast ratio/black levels. Not with a white ceiling, beige carpet and 12-odd predominantly white movie posters it isn't, mate. So, question is: What home cinema mistakes do you see time and again that irritate you?