My friends are much more dangerous than my enemies. These latter – with infinite subtlety – spin webs to keep me out of places where I hate to go, – and tell stories of me to people whom it would be vanity and vexation to meet; – and they help me so much by their unconscious aid that I almost love them.

Letter to Ernest Fenollosa, December 1898, cited from Elizabeth Bisland (ed.) Life and Letters (Boston: Houghton Mifflin, 1923) vol. 3, p. 147.