I have visited Denmark and Sweden, and the most obvious change when you cross the border is that Danes rarely smile walking down the street (or talking to you), whereas Swedes look generally happy.

It is likely a cultural thing, as young (4-6 year old) Danes on the street do some happy, unlike their older siblings and parents;

I am aware that this contradicts surveys that conclude Danes are the happiest people and Swedes aren’t - just recounting my personal impression

These kind of things matter and are very rarely captured in statistics