Oh -- and I suppose whether you think we use "sir / madam" a lot over here depends on just which area(s) of the country you visited. It's a lot more common in the deep south regions (Georgia, Florida, etc.), where there's still a certain degree of class consciousness and social strata, particularly concerning "old money" families who can trace their roots to a particular area back to the Civil War days. In the northeast, and areas west of the Mississippi, it's a lot less common.