In Japan, you will find that every time you walk into a restaurant, they will give you a glass of ice water ... unless the guests specifically ask for snow outside, the waiter will insist on giving you a glass of ice water unless the guests specifically ask for snow outside.
Some restaurants serve hot tea, which is also a reason. Because there is nothing in warm water and hot water, Japanese people think it is rude to entertain guests. But tea is different from ice water, one has tea leaves and the other has ice cubes, which is more attentive.
Today, the concept of "receiving distinguished guests with ice" is still deeply rooted, so even if it is snowing heavily outside, Japanese restaurants will still insist on entertaining guests with ice water. Most restaurants are equipped with ice water.
Anyone who knows a little about Japanese tap water knows that it can be drunk directly, but the Japanese always think that it will taste bad if you drink it directly. But if you add ice cubes to turn it into ice water, the taste of tap water can be neutralized and it will taste better. Drinking cold water will feel less peculiar smell than warm water, and the taste will be clearer, so they will get used to drinking water like this for a long time.
It was not easy to make ice in early Japan, and even after it was made, it would be reduced because of inconvenient transportation. Therefore, the early ice water was not available to everyone, but was only used to welcome distinguished guests, while hot tea was easy to obtain rather than unusual.
Today, although making ice has become simple, the idea that ice is precious has penetrated into the hearts of Japanese people, so it is a kind of respect and intention for Japanese guests to send ice water to restaurants.