Me either, though there is plenty of ink devoted to related subjects. But one can both be pleasant and firm. Not a kid glove, exactly, because that sends the impression that the target can't handle anything difficult, and might mean you make compromises you shouldn't in order to avoid a tantrum. Rather, one can use a velvet glove, even if it has an iron fist in it: https://www.forbes.com/sites/forbescoachescouncil/2021/06/17/balanced-communication-is-it-an-iron-fist-in-a-velvet-glove/