Ferdinand Mount in the New York Review of Books:
Herr Glaser of Stützerbach was proud of the life-sized oil portrait of himself that hung above his dining table. The corpulent merchant was even prouder to show it off to the young Duke of Saxe-Weimar and his new privy councilor, Johann Wolfgang Goethe. While Glaser was out of the room, the privy councilor took a knife, cut the face out of the canvas, and stuck his own head through the hole. With his powdered wig, his burning black eyes, his bulbous forehead, and his cheeks pitted with smallpox, Goethe must have been a terrifying spectacle. While he was cutting up his host’s portrait, the duke’s other hangers-on were taking Glaser’s precious barrels of wine and tobacco from his cellar and rolling them down the mountain outside. Goethe wrote in his diary: “Teased Glaser shamefully. Fantastic fun till 1 am. Slept well.”
Goethe’s company could be exhausting. One minute he would be reciting Scottish ballads, quoting long snatches from Voltaire, or declaiming a love poem he had just made up; the next, he would be smashing the crockery or climbing the Brocken mountain through the fog. Only in old age, and more so in the afterglow of posterity, did he take on the mantle of the dignified sage. Yet even late in life, he remained frightening. His daughter-in-law, Ottilie, whom he insisted on marrying to his son August, though they were not in love and got on badly, admitted that she was terrified of him.
He alarmed people as much as he charmed them, not only by his impatience, his sudden flare-ups, and his unpredictable antics, but by his foul language. In moments of exasperation he would denounce as a shithead any of the great men who had assembled at Weimar—Wieland, Herder, Schiller.
More here.