"To be criticised is not always to be wrong
-- Anthony Eden
"Any fool can criticise and most fools do."
-- Patrick Barlow (though it may have a prior origin)
"Answer not a fool according to his folly, lest thou also be like unto him."
"A fool can always find a greater fool to admire him."
-- Niolas Boilean
"A man of genius makes no mistakes. His errors are volitional and are the portals of discovery."
-- James Joyce
"He who discommendeth others obliquely commendeth himself."
-- Thomas Browne