Two that I seem to remember being mentioned:

1) It has no minimum wage.
2) It has a national school voucher system.

Correct me if I’m wrong. Or perhaps I’ll correct myself later when I’ve got time to investigate.

These studies are not done by people who live in an ideological void but rather, routinely, by leftist academics who know quite well (in advance) that they can choose as decisive the one or two criteria by which a country like Sweden appears to come out ahead of the U.S. and make that “the” measure of human happiness.

In fact, if a criterion such as per capita income — seemingly neutral enough — were used as the gauge, Sweden would rank down with about the 49th or 50th U.S. state — and if that state were governed by a conservative such as Bush, it would no doubt be pointed to as proof positive of the failure of fiscal conservatism.

Luckily, the Swedes have in recent years begun voting for free-market candidates, hoping to stave off their otherwise inevitable decline. Regulation and welfare-statism are rationallly indefensible, extremely harmful, and immoral.

I think the worthwhile point to be made is that there are most of the developed world does an excellent job of increasing human happiness, arguably a better job than the United States, with a much more regulated economic system. Free market capitalism is great, but only when strongly moderated by government intervention.

http://images.businessweek.com/ss/06/10/happiest_countries/index_01.htm?chan=rss_topSlideShows_ssi_5