A Japanese film crew asked a bunch of people from around he world on a Japanese college campus how to spot an American and were given answers such as:

“The clothes they wear then they’re sleeping, they usually wear… for school.”

“They can be jolly?”

“Well, let’s say they usually have a bit more weight on their hips.”

“Make sure everybody gets really wasted and make sure everybody takes lots of shots.”

"They smell like freedom."

here's the video (and it's not all american-bashing).

https://www.youtube.com/watch?t=41&v=Igk4XvzwOCw