It’s the bit of advice every well-meaning parent gives to every child. Just be yourself. Divorced from external outcomes, this wisdom is pretty unimpeachable. Because, yes, it will be hard to ever be internally tranquil if your social persona is critically divergent from your true self. If we stopped there, all would be fine. But we won’t stop there.
Try as even the best Buddhist might, being completely disconnected from social performance is just not how humans operate. Run Just be yourself through this unavoidable lens and its wisdom begins wilting. What if your true self sucks? Is super weird? Cares about things society ignores? Discards communal values? You could very well end up in a position where you reveal the true self, feel calm inside … and end up a total loser outside. Contrast that against hiding the true self, feeling conflicted inside, and gaining much social credibility from one’s deft playing as a poseur. It’s not obvious which path is preferrable.
Perhaps you think back to that lame kid in high school who pretended to like System of a Down when his real passion was Britney Spears, and you say, “Naw, that second path wouldn’t work because we know poseurs when we see them.” Yea, the bad ones. Just consider all the “successful” people admitting they played a “character” to remember that much posing goes undetected. Or really, just look at yourself. You’ve surely gotten away with claiming to like/believe that which you didn’t like/believe; you’ve seamlessly done things you didn’t want to do.