Originally Posted by fastflyer
My feeling is that the non-US tourists understand exactly how to tip appropriately. It's the US-tourists who have lost their bearings.
Tipping is for extraordinary service. No tipping is required for standard service. The rest of the world understands this perfectly.
However, when the rest of the world visits the United States, US establishments do not understand this. When I visited the US for the first time and failed to add the 15% "mandatory tip" to bills for satisfactory service, I was on the receiving end of some surprising comments.