One school of thought says 'authenticity to one's true self' is good, and 'wearing masks' is bad.
By 'wearing masks' is usually meant conforming to convention or others' wishes.
This is all nonsense for very obvious reasons, but, in case the reasons are not obvious, here goes.
Sometimes a person wants to take another's goods, have sex with strangers, and punch people. These come from the self. To be authentic to these would obviously be immoral or at least empty, and likely harmful both to the individual and others. Conversely, convention or another's wishes might suggest one go out of one's way to help others. This might go against internal impulses. Authenticity to self would result in a barbarous response to others' needs.
Unfortunately, the counsel of authenticity to self is monstrous, antisocial, and quite amoral. It's also desperately ineffective, for these and other reasons, which will become clear below.
The 'self' is made of up of base desires, the persistent illusion of separation and attendant notion of 'identity', hatred, resentment, envy, jealously, fear, guilt, shame, and a thousand compensatory and manifesting mechanisms. It also includes a desire to return to God, to connect to others, to be part of a great whole, and to serve. In other words it's a mixed, contradictory bag. One cannot be authentic to self without following two different GPSs at once. Hence the ineffectiveness.
It is clear, therefore, that the lodestar and polar opposite for attitude and action can hardly be 'self good', 'self-denial bad'.
By the same token, societies that function well involve an awful lot of surrender of self for the common good, and it's of note that many of the countries with the highest taxation rates score the highest in terms of human rights, wellbeing, prosperity, health, and numerous other parameters of value.
Thirdly, others' desires, wishes, and drives, like our own, can be good or bad.
In short, it is in everyone's interests, including the individual's, to systematically eliminate any attitudes and actions that stem from the lower self, to be considerate of others, to put others first in many settings, and to put the community and society first, ahead of self-determined objectives: Tradition One's common welfare. The enlightened have always understood this, going back thousands of years.
If I am not for me, who will be for me? And when I am for myself alone, what am I? And if not now, then when? (Pirkei Avot)
Authenticity should quite rightly be to the higher self, but that higher self is often evident only when the lower self is decommissioned, deactivated, or placed in suspended animation. It is only through utter self-forgetting that one discovers who one really is, which is part of a greater whole. The mask of patience, tolerance, kindness, and love turns out to be the authentic higher self, which the individual had never been aware existed.
Of course, this is not a recipe for bowing to harmful convention (jingoism and nationalism, identity stemming from ethnic or other social grouping, suspicion towards foreigners and strangers, the false god of personal ambition) or others' misplaced, harmful, or irrational requests.
As ever, the goal of right living can be reached only through years of work using a system such as the Twelve Steps. Only through long experience and tempering can it be discerned when to follow convention, when to work for others, and when to follow a particular internal lead. In the light of this, the very notion of the authenticity of self becomes moot.