the States:
1. Food Portions
2. Widespread Obesity
3. Tipping
4. Quality of Customer Service/Return Policy
5. Air Cleanliness (except in LA & the Wasatch Front)
6. Amount of Waste
7. Prevalence of strip malls
8. Size of Housing
9. Wide empty spaces
10. Low prices of manufactured goods
I used to include the size of cars, but this is less true now than it used to be, IMO. There are more small cars now in the US, and in the last couple of countries I've lived (Mexico and China) people tend to like big cars and SUVs quite a bit, so the difference isn't as noticeable.