From day one of my first writing job in America, I got warned that the head of the department was wary of me because I was British. This wasn't a concern that I'd switch coffee for tea in the break room, or force my colleagues to wear tweed. He was worried that a fresh-off-the-boat Brit wouldn't be able to handle writing "American."
And I like to think I proved him wrong - but it wasn't easy. George Bernard Shaw once claimed that America and Britain were two nations "divided by a common language" and he's not wrong. British English and American English are remarkably dissimilar in a lot of ways.
As I explained here, I actually think American English is a lot more consistent and logical that archaic British English, but the differences go far deeper than just spelling. What exactly do I mean? Well, look at the example I've produced below. It perhaps illustrates the most significant difference between the way Americans and Brits communicate using the written word:
What differences do you notice between British English and American English?