As for why the US ranked so low, Americans' strong work ethic takes blame; the US ranked lowest for its work/life balance, or really, just a general lack of life compared to work, coming in at no. 32, or third-worst in the world.
Those free refills and fast food came into play, too, as both diet (no. 31) and healthcare (no. 26) weighed the US down. And with an average annual household income of $109,208, the US only came in at no. 22.
On the bright side, the report shows expats integrate well into the American community, make friends easily, and have access to some of the best entertainment, local shops and markets (Walmart, obviously), and utilities in the world. Strip malls everywhere rejoice.