As an European from Spain, in south European countries air conditioners are essential(Greece, Spain, South Italy, South Spain, inner Portugal). But in other countries or places it is not really necessary(north of Spain, France, UK, Germany).

Some days of Summer it is hot there, and they are not prepared for that like people of the South of Italy or Spain, and there is chaos.

It is like when it snows heavily in Madrid: https://en.wikipedia.org/wiki/Storm_Filomena In places like Austria or Switzerland it would be routine. They are prepared and it would be not a big deal, but in Madrid it stopped everything for two weeks.