"Mundane answer is Hypocrisy"
It's not quite that simple though, is it?
It's more to do with mental silos that people apparently construct for themselves:
Silo 1 - On holiday, leisure, etc. in foreign country - enjoy living differently to back home.
Silo 2 - Commuting, work, shopping, etc. in home country - habitual behaviours and 'just doing what what everyone else is doing / what's practical / what works for my lifestyle'.
It's related to the exceptionalism of national / local identities. See also: "Edinburgh is unique / different / special'.