As a speaker of American English, I once told my British coworker that I needed to stop home before our next appointment because my pants were wet.
He responded with “I certainly didn’t need to know that!”, looking surprised that I had told him.
The confusion in this case was based on the fact that in the US, pants means everything from slacks to blue jeans, while in Britain, pants means underwear.
I had gotten the bottom of my slacks wet from walking in the snow, but he thought I was saying that I had peed my underwear.
On a related note, in the 90s there was a popular song that had a female backup singer repeating the line “pissing the night away” over and over.
类似情况还有90年代有一首流行歌曲，唱这首歌的一个女伴唱歌手一直重复一句“pissing the night away（喝了一晚上）”。
The members of the band were all British, which is important in understanding that “pissing the night away” essentially means “drinking the night away” or even just “wasting time all night long”.
乐队成员都是英国人，这一点很重要，因为他们所理解的“pissing the night away”本意上就是“喝了一晚上酒”或甚至只是“消磨一晚上的时间”。
In the US, pissing means “urinating”.
I had a really hard time trying to figure out why anyone would want to spend all night peeing.
Another possible confusion arising from the very same verb is the fact that a person who is “pissed” is drunk in Britain, but really really angry in the US.
That leads to another common misunderstanding.
In the US, if I said that so-and-so was “mad”, I would mean that that person was angry.
In Britain, the word mad is the common term for [en]“crazy”.
If an American asks “Are you mad?”, they’re likely trying to find out what they did wrong; if a Briton asks the same question, they’re accusing you of insanity.
As a fun exercise in a class I taught a few years ago, I wrote the following story that means entirely different things in US and British English:
Yesterday I woke up late for an appointment. I washed up, then pulled on some pants and suspenders, and grabbed a vest on my way out the door.
I drove out toward the university and got a flat. I've had a flat before, but never on my own.
So I called my dad to tell him about it and find out what kinds of things I should be checking for... I ended up catching a lift with my new neighbor, who's really fit, by the way.
As I said before, this is a completely different story depending on which version of English you speak.
In the American version, I woke up, washed my face, put on some slacks and some suspenders (braces in British English), and put on a vest (a waistcoat in British English).
In other words, I was dressed up in nice clothes for my appointment.
Then, on the way to the appointment, my car got a flat tire, but it was OK because I got a ride with my new neighbor, who was an athletic person.
In the British version , I woke up, did the dishes, and put on some underwear, stocking garters, and a sleeveless undershirt.
In other words, I wasn’t really dressed at all.
Then I went across town to rent a new apartment by the university.
In the new apartment building, I got into a lift (an elevator in American English) with my new neighbor, who I found sexually attractive!