What do Americans do that make us stand out?

I’m from America obviously. I read a post on here a while ago that said that the CIA has a class for their agents about how to look less American when in other countries so they don’t stand out as much.

One thing I remember is that they said Americans lean on things a lot. I just read another post that said Americans smile a lot.

So what are things that Americans do that make us stick out? What would make you say “oh, that’s definitely an American”?