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.)