Are you sure about that?
Think about it: only the people of a single one of all participant countries will end up happy (because their team won it) whilst everybody else will end up unhappy (because their team lost).
Granted, there are a few cases of a bit of happiness, like for the people of Cape Verde, without actually winning it but following unexpected very good positions, but those are a minority and tend towards smaller countries (which usually don't have enough population to have enough World-class players even if they're football-crazy, hence why any good result is a surprise).
I would say that logically, all in all at the end of it big single sport world cups like this generally end up with far more people unhappy because of it than the people which are happy.