Last November, I spent the month in Europe traveling to some of the continent's most famous cities. Besides googling the normal amount of words like bathroom, check, wine, please and thank you in whichever foreign language needed at the time, I also searched for that country's tipping etiquette.
Although all countries differ a little on tipping policy, most agreed that a patron would round up to the nearest dollar for good service. Usually ending up in just a few cents for the tip. Extremely good service would warrant an extra dollar or two. As many of you know, America is quite different.
In the US, actually Texas, we tip 15% for good service at a restaurant. For a casual lunch that's around three dollars. At bars we usually tip one dollar for every drink we order. That ends up at a little over 20% of the bill. Other states are different, as in, most states tip 15% at bars, whereas southern states tip their bartenders much more liberally.
Southerners are known for their drinking, and known for their politeness. I guess that solves that mystery.