Steven Pressfield, Turning Pro:

Though the amateur’s identity is seated in his own ego, that ego is so weak that it cannot define itself based on its own self-evaluation. The amateur allows his worth and identity to be defined by others.

The amateur craves third-party validation.

The amateur is tyrannized by his imagined conception of what is expected of him. He is imprisoned by what he believes he ought to think, how he ought to look, what he ought to do, and who he ought to be.

And:

Paradoxically, the amateur’s self-inflation prevents him from acting. He takes himself and the consequences of his actions so seriously that he paralyzes himself. The amateur fears, above all else, becoming (and being seen and judged as) himself.

Becoming himself means being different from others and thus, possibly, violating the expectations of the tribe, without whose acceptance and approval, he believes, he cannot survive.

By these means, the amateur remains inauthentic. He remains someone other than who he really is.