Like jimbocz mentioned, I'm just not British. At all. In fact, I'd say my American identity is something that's become stronger since moving to the UK (back in the US, I never gave it a second thought). It's not something I go around flaunting, rather it's something that's very personal to me. I'll probably always be an outsider here, but I don't mind.
I haven't changed. I still talk the same, have the same ideas/beliefs (though maybe a bit more open minded and accepting of things now vs. before I moved
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), etc.... I dunno, I'm just me! Though I do have a better understanding of British slang words and some cultural references now
My husband's English uncle has lived in the US for over 10 years. He's happily settled there, and is still very English. He's said that he doesn't consider himself American in the least!