I see the common thread in the top 20 Countries for happiness:
8 New Zealand
12 Costa Rica
14 United States
19 United Kingdom
They are all Capitalist Democracies: there is not a truly Socialist Country on the list. Although several of them have elected Governments that describe themselves as Socialist (mainly Scandinavian welfare States propped up by North Sea oil), none of them have Government controlling the means of production, all have private businesses and all protect private property.