Mental health flows from the ceramic jug psychotherapist Lori Gottlieb keeps on her desk. There’s nothing special about the jug—a minor accessory in an office designed with the sort of tidy impersonality common to her field. And there’s no special elixir in it—just water. But all the same, the jug provides a certain kind of healing. When patients are struggling, crying, overcome in some way, Gottlieb, a Los Angeles based practitioner and author of the book Maybe You Should Talk to someone, will offer up a cup of water, pour it for them and hand it across.

In that small gesture is a whole constellation of meaning: concern, care, protectiveness, generosity. It’s a little grace note that’s possible only in person—only when two people…