Had moved from UK (London) to US (New York City) recently, the difference between the two countries had been mind blowing.

I am sure there had been a thread comparing living in these 2 countries or these 2 mega cities (in recent years)? Someone could point me to, then I'd like to contribute.

But if there hasn't much discussion I would like to start one.

1. Food portion, I've heard it is different, but until I see it...
2. Road, much wider here in US, ofc it is because they built the road within their massive land.
3. Diversity, as an asian I've always thought London is pretty diverse, but NYC is on the next level.

Its all about perspective. If you look for differences you will find them. I see far more similarities between the UK and US, than differences.

Anyway, addressing one of your points, from everything I have ever read, or noticed, having lived in both cities, London has more varieties of ethnic communities than anywhere else, and I would say certainly more than New York, which has a smaller number of large ethnic communities, so perhaps it has "more individuals from minority communities", but that is not the same thing as having a wider variety of ethnic communities that London has.

Good points. London seems to me the most international city in the world, and as you well point out London has a wider variety of communities.

The differences between the US and UK are there, yet also similarities beyond more superficial differences.

My intention here is to find the difference, even how subtle it is. I have many friends who had moved back and force from these 2 cities. They chose one place or the other (in different age) because of these differences.

For ethnic communities, I agree that London is a more welcoming place even their sizes are generally smaller. This should be added to the difference too.

4. Cars, those here in US usually cars are bigger in size. But German cars (which is considered as generally good) are less, as compared to Asian cars. Also here in NY state I found electrical cars (such as TESLA) are much less as compared to London, though in CA there are considerably more. Perhaps due to the petrol price factor.

5. Driving, because of narrow road in U.K., people are generally trained better, more polite while driving. Whereas I found disappointed how generally people just don’t yield nor be patient here when driving around NYC.

6. Car signal indicators on the back, this is so subtle but I do find it extremely annoying. In U.K. every car has an amber indicator light, while in U.S. very common they are red, same as tail lights, makes it impossible to tell when it flashes.

7. Roundabouts, I hate them in U.K., complicated and hard to enter and exit, now I am enjoying we don’t have much in U.S, again due to the land and road size.

They do exist here in Jersey, and I hate it because no one knows how they work.

Roundabouts are better, but require a modicum of skill and patience which is often lacking.

Different names for the same things too:
Windscreen = windshield
Boots and trunks
Bonnets and hoods
Discs and rotors
Petrol and gas
etc etc etc

As an ex-resident of Swindon, I will not have a bad word said against roundabouts. I have two on our estate/subdivision and it could do with two more.

I grew up no so far away down the M40 - when learning to drive I was prompty dispatched to the magic roundabout. I now have no fear of them for life.

Agreed!

Also the comment about cars, German I love, Sedans are bigger than whatever Ive driven before in the UK, and love them (Mrs has a SUV). Trucks are not for me but are very much part of the culture here.

From my point of view, the differences seem subtle, especially as a visitor, but living here, I think there is a gulf between the UK and the US.

We’ve generally been perfectly happy with small cars in the US, Honda Civics (back when they actually were quite small, 80s and 90s.), Two or three Yarises, now a Toyota Corolla. We did have a bigger car, Subaru Outback, for the years we were driving all over New York and Ontario with our daughter and her ice hockey goalie equipment. (Which smelled pretty bad, as well as being bulky.) High gas mileage is advantageous, whether gas is cheap or expensive.

In England, I don’t currently have a car, but if I did, it would be a very small one. The main factor there would not be fuel economy, but simply the much smaller parking spots, tight corners, and less space on the roads in general.

Fuel economy would drive any decision for me as well. Remember when I was young and my parents would count out 5 quid to put in the tank. Much better off now but that was hard

I remember two very odd things about my father and his petrol buying habits. At the time I thought they were perfectly normal, of course.

First, he was totally brand-loyal. Only ever Esso. He assumed different brands had different characteristics, would be bad for the engine. Second, he always ordered an exact number of gallons. Why? Why wouldn’t you just fill the tank?

(Thinking through the second one, I wonder if, back in pre-war days, petrol pumps didn’t have automated calculation of the cost of the transaction, and you had to get an exact number of gallons, so the total cost could be calculated? My father’s driving days started in the late 1920s.)

I think that years ago, the pumps would not cut-off automatically so "filling the tank" was more difficult and likely to cause a spill. I seem to remember filling my motor-bike for 5 bob in the '60's.