Ever notice how you argue about the stupidest things with your partner that you would never argue about with your friends? For instance, when I go places with my friends, we never argue about who's driving or who's turn it is to drive. If one of us has a reason to drive or not to drive, that gets stated up front and the appropriate person drives. Other than that, I think we both make internal assumptions about who's driving and then follow body cues about who's car we're walking towards. Sometimes there might even be the question, "who's driving?" usually followed quickly by someone volunteering, "I'll drive."
A and I have started having the strangest car chemistry. We actually have these strange almost-arguments about who drives. He usually uses a teasing tone, but I think he's serious. Usually we haven't established who is driving beforehand and I assume he's driving, because 1. his car is smaller, easier to park and gets better gas mileage and 2. he's always driven everywhere. Maybe he's tired of driving or maybe we just started a trend by taking my SUV camping, but these days he seems to want me to drive a lot more. I don't mind driving if we're going to do "my" plans or see "my" friends, but sometimes I resent it when they are "his" plans or friends.
Maybe we should just ride our bikes?