A servant who offers customers tea in teahouses is respectfully called the Tea Service Master. They provide good service and skillfully brew tea for tea customers. Tea Service Masters wear a traditional costume and prepare tea water in the traditional way. They have a good knowledge of tea and skillfully mix tealeaves. In fact, tea servants normally go through intensive years of painstaking vigorous training before they are able to obtain the title of Tea Service Master.
Once visitors enter a teahouse, Tea Service Masters will greet them with a smile, holding in their hands teapots and cups. After the visitors are seated, the masters will set the cups on the table and pour the water from behind the guests or from above their heads. When the cups are almost full, the masters will raise their hands high suddenly, but not a drop of water is spilled.

This article by Yang Tianqing and Daniel Kister.