Most of the time we aren’t really present one to another, we just bump masks.

William Sloane Coffin, Jr. (1924–2006) American minister, social activist

“Spirituality,” sermon, Riverside Church, New York City (1986-10-26)
    (Source)

Sermon on Psalm 46, Galatians 5:16-26.

Like most writers of sermons, Coffin used the phrase on multiple occasions, e.g., in A Passion for the Possible, ch. 6 "Sexism" (1993):

Vulnerability is a great virtue, as Paul realized when he said, "Whenever I am weak, then I am strong." Without it there can be neither honesty nor intimacy. Without vulnerability we don't really meet each other, we just bump masks.

(Referencing 2 Corinthians 12:10.)