It s up to us to make the choice and up to us to do the building. Being a stock broker, a line dancer, a goth can be as constituting of us as our race or ethnicity. Some part of me is formed by my choice of the kind of Canadian I am. Some other part of me is formed by my choice of the kind of line dancer I am. One writer began the work proposed by the first commenter.
Some identities are entirely optional.
Some are suggested by circumstances of birth but not obligatory. Some are suggested by circumstances of culture or economy. If someone invents a style uniquely their own, people look at it like it's nuts, or a bad thing. See, even though subcultures are accepted now, completely unique individual style is not. I discovered this when I was doing research on the communicative properties of material culture.