It does require an extra mental step, I am mostly ok with the UK, but struggle with the USA terms.

Between English television shows and English friends, I think I know most of the common word differences. The following ones amuse me:

biscuits / cookies
crisps / chips
chips / fries

They amuse me because all of the words describe American foods; just not the same foods as in the UK.

I manage Web content for a living, for international companies, and as a result, I have become verbally dyslexic. I can't remember how to spell color, for example. Is it color or colour? Am I writing a check or a cheque? Am I standing in line or waiting in a queue? Glove compartment, Jockey box, or glove box? Motoring or driving? Hoovering or vacuuming? Bonnet, Boot...

I have my spellcheck set for English U.S., otherwise I wouldn't be able to write anymore.

"Done in" is not an unknown expression in the US. I have never known it to mean seriously ill.

I watch a lot of English comedies and foreign films so I can normally follow most of what everyone is saying

when i back packed thru great britain i got in trouble several times with terminology. i complaned to a brit climber about all the sea gulls on a cliff climb around aberdour, but i said birds instead of gulls and he thought i was complaning about the female climbers,

Each country, even regions within a country, has its own idiomatic expressions. In Berlin, Germany, Berliners use expressions unique to that city and not readily understood by other Germans.

Yeah, it's definitely different based on which part of the US you are from. I grew up in SW Virginia and I heard that expression quite often. Also, I'm "bushed" (tired).

I can generally work stuff out and it's rare that I come across words or phrases that I can't suss out.
Oddly enough, when posting on here I am mindful that my posts will be read by Americans and other almost English speakers ( ) and try not to use terms that could be confused.

I have lived all over the US and abroad as well, and I read extensively. I understand saying done in for exhausted. Colloquialisms are frequently difficult.

I think that's more Australian but I mite be wrong

I speak fluently in both English and American having dated a girl from Hull for five years.

Haha. Well there are some key differences like English and American variations. Centre, Sabre, Sceptical=English, More American: Center, Saber, Skeptical. Slang too can be quite different. Most english slang I still don't understand, even some American slang I still don't understand . I guess we had enough time apart from each other to develop our word usage. There's still some older areas in the US that use the English spelling of some things like centre.

Having had an English ex-mother in law, I understood you to be tired. We do use different terms than Canada, Australia, and England, but it shouldn’t be very difficult to figure out what the speaker means, most of the tome. There are some dialects that are difficult even for the general population of the country of origin! ?

Depends what part of the USA