This is a character design question for most europeans, focusing on people of the Great Britian. Let me explain what I'm doing.
I'm an american designer (college student) creating comic book characters. I want to include a variety of cultures in terms of characters, but I want them to be rich characters containing cultural overtones to contrast those I'm making for
my comic*. The few british contacts I have tease my american ways.

A good ribbing, you might say (or you might not). But the cultural differences just between he and I are at times, stark. I've shown him the Geiko Gecko [http://www.youtube.com/watch?v=cMF8qp0pg_o], and he felt the depiction of his culture in american eyes was absurd.
My question to you folks is,
what are common follys that american writers do depicting brittish characters? It could be an over use of, "'Ello mate," or "Bloody hell!" What are some mannerisms that you feel a brit would never do that americans might? Taking offense to being called a Brit, for example (americans can be overly sensitive to racial issues, whereas this detail is not so extreme in europe, I'm told). Basicly, think back to whatever form of media you once saw/read, and if there was any instances where you, an expert in culture in British ways, felt were absurd, I wanna hear about it.
This isn't a thread about taking the piss out of americans, either. Nor culture bashing. So please, lets not go there.

Thanks.
* I won't be making this comic for some years, while I'm in school. I do work on building up script, and characters in the meantime. That way it's ready to go when I am.