It depends on whom I'm with. I am very shy at times, but when I'm with someone who is not shy I tend to dominate him behind closed doors. However, if I am with a shy guy, I tend to be more gentle...not necessarily submissive, but I allow him a bit more than I would a more aggressive guy. Hope that makes sense.
I'm very shy and a bit of push-over generally if I'm honest. But with my boyfriend, 98% of the time I'm the dominant one. I do it naturally and just get more encouragment from my guy cos he loves it. :)
I think it would depend on the girls mood. A girl with any personality can feel like being dominant on one night, and submissive on another night. So, I think it depends on the mood of the girl, not her personality.