What would I say if you ask me “How do you define myself?”. As a Jew? As an Israeli? As an Objectivist? As a Liberal? I am all of these, but that’s not how I define myself. In fact, I define myself simply as “Shlomi Fish”.
For once, I believe that defining myself as any property of me, does not do justice to myself. I am devaluating myself this way. Furthermore, and equally as importantly, when malicious people try to convince me or other people of doing something, they would say “As a Jew, it is your responsibility to do X”, “Every self-respecting Israeli should do Y”. They will hardly ever say “as Shlomi Fish, you need to do X and Y”.
The first thing a religion or a doctrine tries to take away from you is your personal identity. They want you to feel as if it’s more important to define yourself as a member of their collective, than as the individual that is yourself. No one should fall into this trap.