I can tell this because I'm an American of largely Irish descent.
An Englishman, American, and Irishman, all walk into a bar, and each orders a beer. The bartender hands them their beers; however there are flies in each mug of beer.
The Englishman pushes the beer aside and says, "That's disgusting."
The American pulls the fly out and starts drinking the beer.
The Irishman pulls the fly out, sets it on the counter and shouts, "SPIT IT OUT YOU BASTARD."