Is the home actually badly decorated, like with drywall showing? When I had that problem in a house I downloaded from the gallery I realized that the gym room had drywall behind the mirrors and once I changed that to a painted wall they stopped complaining. I think if you don't have DHD installed the only things they are supposed to react badly to are the really cheap walls and floors and such.
I think I saw a bug report in the help center about the environmental moodlets appearing even when everything was higher quality. So it could be a bug also.
