What features of a city make for happy inhabitants? Most of them are pretty predictable: Mass transit, an environment conducive to raising kids, and affordability all ranked highly in a survey published in Urban Affairs Review.

But, as Kaid Benfield reports in the Atlantic Cities, there was one surprise in this research. It was very important to people’s happiness to see their city of residence as beautiful — but not at all important to see their city as clean.

[T]he researchers found that the perception of “clean streets, sidewalks, and public spaces” actually had a somewhat negative association with happiness. Happy people apparently find their urban environments both beautiful and messy.

Of course, this survey could have been pretty skewed just by how much people love New York and Chicago.