We had my DH's sister & her Canadian husband stay with us a few years ago- she moved there in in the 70's so was pretty much Canadian herself by then.
It was the worst 3 weeks I can remember!! They were rude, offhand & nothing we did was right.
I got told off for drying my washing on the line as ' it made the towels rough. Nothing I cooked (& I am a very good cook!) was up to her standard -although we knew from when my DH stayed with them that she never cooked herself but got takeaways.
DH took 2 weeks holiday & drove them all over the country to visit relatives. We took them to Twickenham to watch an England rugby match as they had said they loved rugby & they moaned all the way through that seats were uncomfortable (never bothered us & we go regularly!)
I could go on but in a nutshell EVERYTHING was wrong.
We paid for everything & they never once offered to pay except on way back from rugby when we stopped to get fish & chips & he offered to pay for theirs!
He did buy 4 cans of beer - when the taxi arrived to take them to the luxury London hotel where they were staying the night before embarking on a world cruise he remembered that he had one can left so dashed indoors to get it!
Not even a 'thank you for having us' or a postcard from ship or anything.
Now we don't do things for the thanks but common courtesy would have suggested just one little 'thankyou' would have been appreciated.
Needless to say we have never offered to put them up again.
We have had some US people stay with us as my DH worked over there for quite a while & they were always charming, polite & a joy to have stay- especially the Mormon man who sent is a lovely picture when he got home of all his children holding up a home made banner saying ' Thankyou for looking after our Dad!'
I do't know what happens to people at the border between US & Canada!
Things you find stressful that other people don't notice.