[Germanika]

>Look how cold some countries and regions get?

As someone from said countries and regions, people living outside freeze to death here. Long before you get to that point your water pipes will freeze, leaving you without running water. The pipes will then burst and flood your house if you don't address it quickly enough. You can certainly heat it to a lower temperature and occasionally crack open a window for some fresh air, but there's a difference between conditioning yourself to be comfortable at 17C and -30C.