I have witnessed and greatly enjoyed the first act of everything which Wagner created, but the effect on me has always been so powerful that one act was quite sufficient; whenever I have witnessed two acts I have gone away physically exhausted; and whenever I have ventured an entire opera the result has been the next thing to suicide.
Mark Twain's Own Autobiography: The Chapters from the North American Review (ed. Univ of Wisconsin Press, 1924) - ISBN: 9780299125400