"So, Pete, I can't use any Brit terms because I'm an American? Strange.."

I'm betting that because you ARE American, your use of the British terms may have set some folks off. (Wish I could "talk with my hands here")

It's like me.. Being from TN, I probably wouldn't get many "YaHoo's" if I decided to throw some Aussie slang into my emails.

There would probably be some thinking "what???", while others maybe really put off by my attempts.

Pete