What is public is irreducibly performative. Authentic friendship revolves around what is not public, what cannot be performed, what is hidden and what is, so far as anything human can be, un-calculated.
That which cannot be public is the currency of friendship, the guarantor of intimacy. Shared secrets, mutually-disclosed but socially-unacceptable sentiments, are the arch-reality against the surreality of performative acquaintanceship.
We live in an economy of celebrity and publicity, commercial pressures focus technological innovation on convincing humans to be more public. Thus, private friendship, real friendship, born of intimacy that cannot be performed, friendship that entails taboos and violates cultural norms, is pushed further into the margins of social experience.
That what is positive can generally be public means that as often as not, negativity is the axis around the authentic-dependent friendship forms.
The essence of human communication experience remains privately-shared, socially-untenable asides about how much we detest one another.