Ruskin frequently scolds his listeners in his lectures. Here’s an example, from Sesame and Lilies, “The Mystery of Life and its Arts” (Works, XVIII, 168-169).
In that slow way, also, art can be taught — if you have faith in your guide, and will let his arm be to you as an iron bar when need is. But in what teacher of art have you such faith? Certainly not in me; for, as I told you at first, I know well enough it is only because you think I can talk, not because you think I know my business, that you let me speak to you at all. If I were to tell you anything that seemed to you strange you would not believe it, and yet it would only be in telling you strange things that I could be of use to you. I could be of great use to you — infinite use — with brief saying, if you would believe it; but you would not, just because the thing that would be of real use would displease you. You are all wild, for instance, with admiration of Gustave Doré. Well, suppose I were to tell you, in the strongest terms I could use, that Gustave Doré’s art was bad — bad, not in weakness,- not in failure,— but bad with dreadful power – the power of the Furies and the Harpies mingled, enraging, and polluting; that so long as you looked at it, no perception of pure or beautiful art was possible for you. Suppose I were to tell you that! What would be the use? Would you look at Gustave Doré less? Rather, more, I fancy. On the other hand, I could soon put you into good humour with me, if I chose. I know well enough what you like, and how to praise it to your better liking. I could talk to you about moonlight, and twilight, and spring flowers, and autumn leaves, and the Madonnas of Raphael – how motherly! and the Sibyls of Michael Angelo – how majestic! and the Saints of Angelico – how pious! and the Cherubs of Correggio – how delicious! Old as I am, I could play you a tune on the harp yet, that you would dance to. But neither you nor I should be a bit the better or wiser; or, if we were, our increased wisdom could be of no practical effect.