This is also a matter of habit. I live in Japan, and I was not used to it at first, but it is still difficult to give up now. Even if you go to a restaurant in the cold winter in Japan, you will be served a glass of cold water. Even old people are the same. According to the custom of China people, it is best for the elderly not to drink ice water, but there is no ice water here. Plus Japanese tap water can be drunk directly without boiling. Because they are clean ... but people who are more particular usually buy water to drink ... and we have to add ice when drinking.