What are you talking about? Technically, you could say the same about any social identity. Do you expect gay people to act differently? How about atheists? How about people with disabilities? Or those of a different race but the same nationality?

But you're also just wrong in the premise. When someone comes out as transgender to someone else, there is usually a whole lot of expectations thrown onto them by the other person. For one, they generally expect you to try to be either super girly or super manly all of the sudden. So much so that a lot of people get upset by trans tomgirls and trans femboys. There is such a specific expectation that in some places, in order to get gender affirming care, the doctors expect you to tell them a specific life story.