Oh, it's the same in China. I can't imagine not wearing a coat when it's +8°C (seriously, there is nothing worse than being cold), but the weather doesn't seem to bother other people that much. I can only surmise that we are spoiled by our central heating (you have to open windows from time to time because radiators are scalding hot). It does feel different when most buildings are not heated like that (or sometimes at all — electric heaters are largely inefficient when it comes to heating a house, by the way) in winter; I was in the UK once and we lived in a rather cold house, and the whole concept of dressing "properly" and warming the bed before getting in was heartbreaking, but apparently I was the only one who was freezing all the time. Maybe when the temperature is barely tolerable everywhere — at home/work/university/etc. (how can one live when it's just 18°C at home? how?) — you get used to it in the end? I don't know, it's just a guess, but I suppose it's some kind of forced conditioning to the cold.
It is similar to the way other people in cold climates try to acclimatise their children for the conditions they must live in.
In the UK it is not unusual for cold spells to come and go very quickly, often there is no point in putting on warm clothes when it will be warm again in less that thirty minutes. Also we know from experience that if you can acclimatise your skin to the cold conditions you will have a better chance, within reason to survive getting stuck in the cold for several hours, whilst you get found again or manage to find your way home. The only time there are major problems is when being out unprotected for one or two nights on some days of the year in isolated or windswept regions, when exposure and wind chill can kill. The uk is so small It is unusual to be out in the cold for long periods, unlike in other countries, it is usually possible to get into a warm place within about five hours, long enough to watch a football match in the freezing cold for only two hours and then be home in the warm again for a hot meal or a hot beer. We do not often feel or have the need to protect from the cold for long periods. Plus we know from experience that even if you work outside in the cold the best way to get warm is to generate body heat by working. If you are not working then the best way to get warm is to walk briskly and keep extremities in pockets, not gloves.
Babies get trained from a very young age by being allowed out in near freezing conditions for short periods. If they are normal children they will get warm by playing and their muscles will generate heat.