One difference between the US and the UK which caused a few weeks of utter confusion for me is the attitude to cats and the outdoors.
In the US, many people prefer to keep their cats indoors. When I was a volunteer at the SF SPCA, in fact, we made people sign a form promising to keep their cats indoors only. Cats allowed outdoors have much shorter lives- they get run over by cars; they get into fights with dogs; in certain areas, they are the losers in encounters with coyotes or other wildlife.
In the UK, it is assumed that cats must go outside. When we looked for rental housing, we'd mention the cat, and agents would say, "Oh, but this is a flat" or "There's no garden." Which confused the daylights out of me. I'd be all, "Yes, I know it's a flat..." or "And...this is relevant how?" But of course, they skipped straight from "We have a cat" to "It'll have to go outside".
Whereas Chloe, in her short but peripatetic life, has lived in houses with yards where she was allowed out, to apartments where she was kept in. If outside is available, she goes, but otherwise doesn't really care either way.
These people? Definitely not Britons.