In my second month of being in Philadelphia, and by extension the US, I have had certain novel experiences that in some cases were interesting, while in others came as a shock to me. I have outlined some of these culture shocks which I have experienced since moving to the US from Germany.
More Vibrant and Open: From my own personal experience, people are more open or outgoing here than the average person in Germany. For the most parts, the people in Germany are usually more reserved and keep to themselves most of the time. It was not very common for someone to walk up to me on the street and strike up a conversation, which was the reason I was somewhat shocked when I had such a random encounter with a young lady somewhere in center city. Besides the unplanned encounters with strangers when outdoors, it has also been relatively easier to develop acquaintanceship here, even more so at Drexel.
Places are Open on Sundays: I recall my first week in Philly when I was in a hurry to go get groceries on a Saturday evening, because I thought the store would be closed the next day. It took some adjusting to learn that almost every place (there may be very small exceptions) in Philadelphia, and perhaps the US, is open on Sundays. This is not the case in Germany where most places are closed on Sundays due to laws that dictate Sunday as a day of rest. In Philly however, grocery stores, restaurants, clothing shops, etc., all remain open even on Sundays.

Tipping: Tipping culture is very prevalent in US society. Back home, people do tip but mostly when they have received very exceptional service or just out of sheer benevolence. However, in the US, the tipping system seems rather mandatory and at times, it is incorporated into the final bill, regardless of what service was rendered or its quality. I have come to understand that the reason behind this may be because the minimum wage for such jobs is quite low, so most of the workers depend heavily on these tips. So next time you get a quick late-night delivery or eat at a restaurant with great service, do not forget to leave some appreciation for these workers 🙂
Measurement System: If I had a dollar for every time I have had to convert from Pounds to Kilogram or Fahrenheit to Celsius since coming to the US, I would probably be giving Jeff Bezos a run for his money. Even when telling time or writing the date, this problem persists as well. The date format here is the month before the date; I, and probably the rest of the world, am more familiar with writing the date first and then the month. As a result, I had run into some problem earlier this month due to my misunderstanding of this date format. I would say it takes some getting used to, but it probably may not, especially if you are here for a short time. However, for the sake of eliminating misunderstanding that may lead to some problems, it would not hurt to familiarize oneself with the imperial system of measurement while in the US.