As you begin your tour of the United States, you may as well know that one American national trait which irritates many Americans and must be convenient for our critics is that we relentlessly advertise our imperfections.

Meaning of the quote

Americans often openly talk about their country's flaws and shortcomings, even though this can annoy other Americans and give critics an easy target. This is a common trait among Americans that visitors to the United States should be aware of.