"I always go on until I am stopped," Shelley said in later years to his friend Trelawny, "and," he added, "I never am stopped." But sometimes he was stopped. And when he was, he became uncontrollably enraged. The "violent and extremely excitable temper" of the child, and the adolescent’s frenzy on the loss of Harriet Grove rose to a new pitch in the wild descent upon Field Place — "Bysshe, Bysshe, Bysshe … Aye, Bysshe, until you’re deaf" — with its whirling insults and fantastic charges. These rages — "violent fits of passion" — which apparently were as rare as they were violent, Peacock later (1813-1818) recognised and talked about in private but omitted from his printed account of Shelley, and Merle records records one of them in his picture of Shelley’s furious anger when his anti-religious opinions were challenged:
As I proceeded he became angry; indeed almost furious. “Do not,” said he, “talk such stuff to me; I hear enough of it at home, There is my father, who, with a painting of that imposter, Christ, hanging up in his library is sometimes vain enough to suppose that he can bring reason postrate before absurdity. I have too many of these follies before my eyes: they drive me mad!” And mad, indeed, he was. I think I see him still. His eyes flashed fire; his words rolled forth with the impetuosity of a mountain-torrent; and even attitude aided the manifestation of passion … “No more of this, Shelley, or from this moment we become strangers, as we have been friends; nay, if it must be so, enemies, as we have been brothers.” “Have your own way, mad fool!” exclaimed Shelley; and, taking his hat, he quitted the room.