Most of the living room furniture Mattel creates is not 1:6 scale. It’s small. I don’t know if they do this to save money or space or both. Maybe they do it so dolls without articulated knees can appear to be sitting comfortably.
Because of this fact, most people who play with barbies a lot or make dioramas like to use non-Mattel couches and other furniture.
Not only do the Mattel couchs look ridiculous but they are hard to use. In setting up the photo for this blog entry I sat the two dolls on the leopard setee with very little extra work. When it came to positioning the other couple, it took five or six attempts. This was due to the size of the couch, the material the couch is made of and the fact that I was using un-articulated dolls.
I try to find ways to cut down on frustration during play as much as possible so having a few nice custom-made couches around is really nice. They look good, are sturdy and can usually seat more dolls than Mattel couches.
They are also nice if one reason you play with barbies is because you enjoy interior design. Look for custom furniture on ebay and Etsy and you should find something to your liking.
A favorite designer of mine is Vanessa Morrison. She makes one-of-a-kind barbie furniture and sells it on Etsy.