“Normal” is a statistical concept determined by the set of things that happen to be the case. Similarly, a “normal person” is a statistical construct that we collectively define through our actions. Whatever most people do is normal for people, and whatever most members of a particular group do is normal for that group. No actual person will have every normal quality, but that does not change the fact certain qualities are normal.
I would say, then, that there is such a thing as normal; and while it is not itself a template of expectations to be met, what is normal tends to drive people’s expectations insofar as they expect common things to continue being common and uncommon things to continue being uncommon. Doing things that are not normal will surprise others, and they will be more surprised the further from normal your actions are.
While diverging from normal may be surprising, though, it should not be considered inappropriate solely on the grounds that it diverges from what is common. That is, we should not take what is normal to be normative. The expectations that people have in these cases are not—or at least should not be—moral expectations. It is one thing to be shocked to see someone riding an elevator facing backwards. It is another to have them arrested for it.