I don't understand, but I'm COLD

I was standing in the post office yesterday where, despite the fact that due to air con it was already about 18 degrees Celcius (which is . . . I don't know . . . it's COLD, I know that). And on top of that, there was a fan blowing. Right on me. So here I am, Minnesota born and bred, freezing my tail off on a tropical island. Perhaps fitting given that it was December 23rd.

But it brought me back to this baffling question - why do they keep it so insanely cold inside? There is no reasonable explanation. It's not like these people transplanted from Alaska and can't handle the heat. Do they like to waste electricity? Do they like to spend money on a whole second wardrobe to wear indoors? Is this a silly way to demonstrate wealth? Do they just not like wearing shorts?! (side note: I have had almost no luck finding shorts here, even capris).

To add oddity upon oddity, many of them don't run their air cons at home - they just leave doors and windows open. I am at a loss to explain this, but I am really wishing now that I hadn't sent all my winter clothes back to the states. If you plan on coming to visit, don't forget your jacket!