At a Western restaurant, the first question the waiter asks is what kind of water you want to drink: bottled or tap, with gas or without. At a Chinese restaurant, the first question is what type of tea you want to drink. You would never be offered water, because the Chinese consider it unhealthy to drink water during meals.
During dinner at a local Chinese restaurant, one of our friends finally asked the waiter why the Chinese will drink tea and soup at dinner, but won't drink water. The waiter explained that tea is good for cleansing your mouth between bites, and that soup is healthy and tasty. However, he said, drinking water will dilute the stomach's digestive acids, making it more difficult to digest the meal and leading to indigestion.
Americans and Chinese also have different views on drinking cold water and other drinks. Most Americans like their drinks cold, preferably with ice cubes, and don't like to drink room temperature water. Most Chinese, however, drink room temperature or warmer liquids, like tea, and avoid cold drinks and ice. They feel that the cold temperature is a shock for one's stomach and internal organs, and that warm fluids are healthier for the body.
(selected from 101 Stories for Foreigners to Understand Chinese People by Yi S. Ellis and Bryan D. Ellis, published by China Intercontinental Press in 2012)