I don't like wearing a coat even in the middle of winter, as I dislike the feeling of suffocation as one enters the indoors.
Consequently, I opt to wear a T-shirt, and then only a sweater, which is full of small "holes" by their nature through which bitter winds would inevitably blow.
When I went to Hakata the other day, it was snowing and the temperature was very low. As I ventured out of the hotel to have supper, the bitter wind was blowing through my sweater onto my bare arms with an astonishing force. It was at then that I felt a "danger" for my life.
Undaunted, I just hurried on to the restaurant, with my arms gathered around the chest area to protect and shield.
Once I was in the restaurant, I was OK.
Unrepentantly, I go about in the winter Tokyo today with my T-shirt and the sweater. People are astonished to see me without a coat. It can certainly make you alert, reacting to the changing weather. And it is just great once you are inside, without the nuisance of having to get rid of the coat.
It is just the winter of Tokyo that I have to withstand, which is relatively mild compared to, say, one in Russia.