One being that, your belief about what you feel about yourself is not your authentic, true self. These beliefs are generally narratives, some deeper than others. Examples of narratives include: "I am successful"; "I am a failure"; "I am smart"; "I am dumb"; "I am socially graceful"; "I am socially inept". Rather that arising from narratives, no matter how deeply held, the authentic self arises naturally and spontaneously from the transcendental ground from which all phenomena arises from.
In other words, "be yourself" is once both good advice and bad advice. It's generally where you want to go (at least from the perspective of Shaiva Tantra). But you need sufficient wisdom -- that is, awareness -- of knowing your true self.
The other is that what arises naturally and spontaneously may not be something you want to arise naturally and spontaneously. Someone who is naturally and spontaneously an asshole is still an asshole. Part of the practices Shaiva Tantra involves becoming. If you want to be a compassionate person, it isn't enough to put on a social mask so people see you behaving in a compassionate way; that is not authentic. It isn't enough to want to do it, or to feel it welling up deeply inside of you. Rather, it is becoming (that is, the transformation into) the person such that being compassionate is natural and spontaneous.
Shaiva Tantra is not the only teaching that has something to say about this subject. Another one I learned from books written by that trickster, Carlos Castaneda, this idea of impeccable intent. It's another way of saying "integrity" or "authenticity", or "wholeness". There are others -- Lao Tzu, for example. Rumi.