I'm a bigger dork in my head than I am in real life. Which may or not be surprising to you depending on how well you know me. For instance, I'm not typically nervous about meeting new people. At least not at first. It isn't til right before it happens that I worry that I'm going to start speaking in an accent. Seriously. I sometimes have to give it thought in order to not pull a Phoebe. What if I was to meet some of Mark's family or friends and suddenly slip into a British accent?
I've joked about doing it enough that I feel I might just do it unknowingly. I have a pretty easy time picking up certain accents (Southern, British, Irish, Jersey, to name a few). When I worked on the phones and would talk with a caller with a heavy accent I would have a hard time not talking back to them with the same accent.
I just thought I'd share a bit of my neurosis with you.