Americans, as you may know, have a reputation for being talkative (a nicer word for loud). We tend to have a lot to say, and we tend to feel pretty comfortable saying it. Still, there are some taboo topics that even Americans don't like to discuss. So, when in conversation with a chatty American, try not to bring up...
Money makes the world go round, and Americans are, at times, "all about the Benjamins" (Benjamin Franklin appears on our $100 bill). However, just because money's on your mind doesn't mean it should be a key part of your conversational repertoire. It's c**idered impolite to ask about someone's salary, or to discuss other matters of personal finance.
"Americans have famously enormous appetites – I once went to a French ice cream shop where the sizes were small, medium, large, and American." But discussing someone else's weight is c**idered extremely rude in the United States. A person's weight is private, and making comments about is definitely c**idered disrespectful.
We have all kinds of political opini** in the United States, and the range of popular beliefs runs across a much wider spectrum than in some other nati**. Just follow an American presidential election and you'll see that our political system is hardly even civilized. It's not that talking politics is an unforgivable taboo in the United States, just that it's probably not such a good idea to bring it up unless you're prepared for a potential argument.
Similarly, though the United States is a relatively religious country, personal beliefs are rarely brought up in casual conversation. It's a good idea to get to know someone a little bit before discussing his or her religious backgrounds or practices. Faith is usually c**idered a private matter (though it certainly plays a sizable role in the American public sphere as well, particularly amongst politicians who are keen to show an allegiance to it).
First of all: We call it "soccer", not football. Americans are proud of their homegrown sports like baseball and American football, and professional soccer is relatively unpopular. We prefer our sporting events to be saturated with American patriotism and plenty of game-day snacks. If you want to talk soccer with a stubborn American sports fan, be prepared to start with the basics—and to encounter a whole lot of resistance to the world's favorite sport.