In the United States, there are lots of things that make people go into cultural shock when they are just visiting or actually moving in for the first time. When compared to other countries, there are several things considered as normal in American, but may be frowned at in other countries and continents.
One of the major things is dressing. In America, dressing is on a whole different level. It is easy and common for people to walk around wearing very revealing clothes that leave nothing to the imagination. One might say it is because it is a free country, but in some European countries, decent dressing is a must, and you can be penalized for going contrary to that.
Secondly, Americans hardly see the need for propriety. An average American can move around in sweatpants or gym outfits all day. In most European countries nd even other countries all over the world, wearing sweatpants, night clothes, or gym outfits will give you several side eye looks from people as you move round.
Another thing that is prevalent in America is the cashless policy. This may not exactly be considered trashy, but having everything charged to your card is not usually the best idea most of the time. It can be important to have some change with you at all times as seen and confirmed from countries in Europe.
Finally, showoff is and has been a distinguishing factor between Americans and other countries and continents. One way to identify a rich or wealthy person or family is by excessive showoff in terms of media and portrayal in public. In other parts of the world, wealth is neither associated with being loud or being popular as it is assumed that your wealth can make you a target. It is not surprising how rich or wealthy people and families can live and extend for generations without being in the front lines of the media.