My name is Shandy, and I'm an authorial construction. I constructed myself to see if Pavlovian Penises would attract editors.
I constructed another self to teach impressionable Chinese college kids English, an almost always cheerful, patient wise person completely at odds with the Paul that finds out his plane is overbooked or is stuck listening to his aunt diss Obama because he was just a law professor instead of a businessman like GWB. They are completely unaware of Shandy, aside from my politics.
In high school I adopted a Spock persona to survive the rejection inevitable to overweight nerds. In college I was a borderline Ayn Randian to avoid feeling bad about being born a white man (but I couldn't get along with the other Randians because they were using Rand to justify being Republican, and I couldn't go that far).
While I recognize those as defense mechanisms, I do think if you don't assert your own contruction of yourself, other people will impose one upon you.