Sometimes “oh” is a complete sentence.
If somebody tells me his plans, “oh” may be more respectful than offering my unsolicited advice.
If somebody tells me about her world, “oh” may be kinder than “that reminds me of the time when I. . . .”
If somebody gives an opinion (especially one I don’t agree with), “oh” may be more welcoming than airing my own views on the subject.
“Oh” takes the pressure off. It lets the other person speak in a more leisurely way, and it lets me listen in a more leisurely way. It gives us both breathing space.
Sometimes, with words, less is more.
“[P]ay attention . . . also to the interests of others.” Philippians 2:4