You're not getting faster service, you're using an additional non-verbal signal. Moving your glass to the edge is how you say, "Please refill my glass." Simila

You're not getting faster service, you're using an additional non-verbal signal. Moving your glass to the edge is how you say, "Please refill my glass." Similarly, if you're in a Chinese restaurant, flip the lid upside-down on the teapot to ask for more tea.