What should you never say to a British person?
When I studied abroad in the UK, every room came equipped with an electric kettle for making tea.
I foolishly asked the British students, “Why do you need a kettle? Can’t you just make your tea in the microwave?”
At least they didn’t kill me.
Never assume that a British person is English.
It will be highly resented by the Scottish, Welsh, and certain Irish people.
And never assume that what English people do is typical of what British people do.
There are over 130 languages spoken in Britain, and the Scottish, Welsh, and Irish have their own languages, apart from that, they sometimes speak English in accents that are indecipherable to most English people.
Also, there are very few English people who speak English in the way it is spoken by News readers, actors, or politicians.