At times my work has brought me into contact with Americans and in general they just do not get sarcasm and satire. Obviously not true of everyone but in general in my experience, Americans (not sure about Canadians) take things that you say very literally. Take my advice, when dealing with people from the USA, as a default, avoid irony/sarcasm/satire and even humour until or unless you know they will appreciate it.…
I would lay a very large bet that the "/s" tag is an American invention. I find people pleading for unambiguity in sarcasm on the internet amusing, "sarchasm" being one of the better words invented over the last few decades. (Also an American invention?)