What Britishisms most baffle Americans? What Americanisms most baffle Brits?

[Mangetout]

I’ve made a spinoff thread about corrections in order to stop hijacking this thread on that topic.

Do you correct people a lot? What's your motivation?

A spinoff from a point that came up in this thread… Do you routinely or frequently find yourself correcting other people’s grammar, or choice of words? Or do you find yourself telling people that they are doing some activity or action wrong, and should do it a different way? Why do you do it? What, if anything, do you get out of it? What purpose is served by it? What bad things do you feel might happen if you didn’t do it? Full disclosure: my own motivation for asking this question is tha…