Many aspects of American culture are admirable, but there are also quite a few things that I find odd. For instance, why does the United States use Fahrenheit or miles instead of Celsius or kilometers like almost every other country around the world? Why are there such huge gaps in between toilet stalls? Why do Americans expect waiters to constantly stop by asking if they need anything? More importantly, why are customers obligated to leave an additional tip on top of the cost of the meal itself — one that constitutes a hefty 15 to 20 percent of their bill?