I've got scripts. Scripts for when I have casual conversations with casual friends; scripts for when I talk to higher-ups in any given echelon; scripts for talking to teachers, talking to bosses, talking to waitstaff and librarians and co-workers. All these manuscripts are stored in the attic of my mind and when we talk I venture up the stairs and choose the one that most closely pertains to you. If you get wily and stray from your lines, well, then the joke's on you because I will trip all the hell over my tongue and mire you in a mess of words that neither of us can save ourselves from.
If I don't play a conversation out in my head before I have it, it's a lost cause. Something as simple as ordering a sandwich can really get weird.
During the pivitol transitions of adolescent life (going from middle school to high school, for example, or from high school to college) I always imagined re-inventing myself as a more open, talkative person. Any one of my current acquaintances can you tell how that worked out; and now, as I look warily toward the Great Transition In The Sky (from college to the real world) I realize it will never happen.
It's sort of a relief knowing I can remain the way I am, knowing that this is the way I operate. When I need to trick people into thinking otherwise, I'll just grab for the right script and give it a whirl. Sometimes it gets weird, but I realize its probably weirdest for me. And I can stand that.