It's a lot like clothing. People have a lot of control over it, and it is used in all their social interactions. With a lot of effort - perhaps alienating your local community in the process - you can change it to pretty much any other community's norm. Despite such theoretical freedom, most of us feel quite restricted about it. We don't even think about it usually; we just do it like how everyone else in our community in a similar social status does it. So it almost unavoidably and automatically indicates something about your cultural background and social status.