I moved back to the US from the UK after 4 years. Here are 9 things that have surprised me the most so far.

From the moment I hopped in a taxi at JFK Airport and began the drive to Manhattan, I started to notice just how much larger than life things are in the US compared to back home — from the width of the highways and cars to the moment I ordered my first bagel in New York City, which was so big it was basically impossible to take a full bite.

I've also noticed that the smallest to-go cups at coffee shops in the US are way bigger than the largest I'd had in the UK, and the portions of meals I've eaten at restaurants in America so far have been more than I'm used to.

I'm far from the only one who's picked up on how portion sizes vary vastly in the US from the UK. Insider's Food Wars senior video producer Joe Avella previously wrote about being continuously shocked by how much larger fast-food items are in the US than in the UK. At McDonald's, for example, he discovered that American drinks are 89% bigger than their British counterparts, whether you order a large or small.

Having lived in the US previously, I was somewhat familiar with how important it is to tip when you go out to restaurants, which continues to baffle people from different countries where the practice isn't considered a cultural norm.

That said, knowing where exactly a tip is appropriate and the amount to give has been confusing. When buying a coffee or a drink at a bar in the first week of my relocation to the US, I found myself in an awkward spot deciding whether or not that warrants a tip and, if so, how much to give.

So far, I've learned that it can vary, but that the safest best whenever you have doubts is to leave a tip — no matter the situation.

Unlike the US, tipping isn't mandatory in the UK, as most places add a mandatory service charge to a bill, which in my view, might explain why customer service at restaurants is generally quite different.

Since I'm still in the process of setting up my apartment, I've done a lot of eating out in NYC. Granted that hasn't been the best for my budget, but it has made me appreciate how much more effort servers in the US put into giving customers the best dining experience possible. So far, I've had instances where dishes have arrived late and have been taken off the bill or where servers have taken time to get to know a bit about me while taking my order. That kind of warmth and charisma is rare to find in the UK, from my experience.

My favorite place to grocery shop when I was in college in the US was Trader Joe's, which sadly has yet to open any locations in the UK. One of the reasons why I loved it so much is because of the quality and sheer variety of its frozen food. The chain's frozen pasta and dumplings are some of my favorites, and I can't wait to explore new staples now that I'm back in the US.

The same can't really be said for what's available in the frozen-food aisle when grocery shopping at stores like Sainsbury's and Tesco in the UK, in my experience. Besides the odd pizza, I've generally avoided purchasing frozen meals in the UK in favor of going for fresh produce because they aren't as appetizing or as diverse as at grocery stores in the US.

I knew that Americans loved air-conditioning in their homes, but I genuinely was taken aback when I felt the cooling breeze of an AC unit while riding the subway on an unseasonably warm day during my first few weeks in New York City.

Back in the UK, not only do most homes not have AC units, but neither do most of the trains that run through the London Tube. In the summer when temperatures soar, you can often hear announcements over the loudspeaker warning people to stay hydrated and seek assistance if they find themselves struggling due to how hot it is on public transport.

As someone who grew up with a Dutch father who is all about efficiency, I've been shocked and frustrated at how many long lines I've seen in the US since moving back.

I first noticed it when my little sister took me to grab a bagel at Tompkins Square Bagels in the Lower East Side. In fairness, we arrived around midday during the work week, so I assumed there were a lot of people there to grab lunch, but I still thought it was wild that customers were happy to wait in what looked like a line of over 30 that wrapped around most of the restaurant.

As we joined the back of the line, I turned to my sister to point out how crazy it was, to which she said: "Americans love lines. I've seen people join the back of lines without even knowing what they're queuing for."

One of the biggest takeaways I've had since moving back to the US is the realization that Americans love a parade. From watching "Friends" growing up, I knew that the Macy's Thanksgiving Day Parade was a big thing that happened each year, but I had no idea that people in the US throw a parade to celebrate pretty much any holiday.

For Halloween alone, I saw two different parades, including one where dog owners dressed up their pups in costumes.

Aside from the official royal parade during the coronation of King Charles III in May, I've never seen anything on the same scale in the UK.

I'm not a huge drinker, but I will say that one of my favorite aspects of living in the UK is its pub culture.

People in the UK will usually say they have "a local" pub, meaning one that they frequently visit. For them, it's not only a place to have a few drinks with friends, colleagues, and family, but where they can enjoy meals.

Most pubs I've visited in London have a super homey, laidback atmosphere. Unlike the bars I've visited since moving to NYC, pubs back home rarely have loud music, and visitors are often allowed to bring dogs and young children along with them.

One of the things I was really looking forward to before moving back to the US was traveling within the country to the Midwest and the West Coast, places I didn't get the opportunity to visit during my college years.

But unlike the UK, where different cities are often a train ride or short flight away, everything is so much more spread out in the US, which is something I've only just started appreciating since looking into booking vacations.

The idea that it takes over six hours to reach a different city within the same country by plane is a wild concept for someone from the UK, where a flight to France and Spain is only a couple of hours.