Good heavens, Tevye - let the good rabbi finish his explanation!
During the wedding of Tevye's daughter Tzeitel, Perchik wants to dance with one of the women. An argument breaks out that this is not allowed, so they ask the rabbi. As the rabbi gets up to speak, he says, 'Well, it's not exactly forbidden, but -' At this point, Tevye cuts him off.
That is so not nice.