No Shoes, No Sleeves, No Problem

It's January. I was in the local Old Navy Danvers Massachusetts location the other day and witnessed a lady in front of me with shorts on. Back in November when the temperature was in the 20's I took this picture in a restaurant:

'What's the big deal?' Some Americans may ask. (Granted, most Americans - including myself - would NOT wear shorts in the winter time.)

The reason I took note (and pictures) was because I have surprised quite a few people in Croatia when they observe me lacking a particular piece of clothing. Take for instance their reaction when I don't have slippers or shoes on in the house. They'll scurry to grab their closest pair of footwear and demand I put them on. I'll get the same raised eyebrows if I only have a t-shirt on (in the house) during the winter time.

Croatians - and probably most Eastern Europeans - are very particular about keeping warm. Don't expect to find ice-cubes in your Coke if you visit. They give you a sore throat. Never have two car windows down at the same time either. That would cause a draft. Babies are bundled in the summer, feet must be covered by two layers when in the house, and there is never any sitting on the ground - no matter what your age is or what season it happens to be.

Why?

Still haven't quite figured it out. Eastern Europeans - here's your chance. Explain to us what the big deal is. Until then, I'm staying slipperless in the house.