A well-read fool is the most pestilent of blockheads; his learning is a flail which he knows not how to handle, and with which he breaks his neighbor's shins as well as his own. Keep a fellow of this description at arm's length, as you value the integrity of your bones.
François duc de La Rochefoucauld, Stanisław I Leszczyński (King of Poland) (1851). “Moral Reflections, Sentences and Maxims of Francis, Duc de la Rochefoucauld”, p.181
