Taking Leftovers Home
It doesn't seem weird until you consider that other places don't do this, but taking leftovers from your dinner is actually kind of gross. This is necessary for America because the portion sizes are usually way too big for one person to finish in one sitting, but in other countries, portion sizes are much more manageable and don't require a doggie bag.
Giant Meals
That being said, Americans live to eat. The portion sizes have only gotten bigger and bigger over the years, and with the option to supersize meals at most fast-food chains, the belief that "bigger is better" prevails. But when you notice the size of the American waistline, you'll probably realize that that definitely isn't always true.