To forget one's purpose is the commonest form of stupidity.
— Friedrich Nietzsche

The commonest fallacy among women is that simply having children makes them a mother - which is as absurd as believing that having a piano makes one a musician.
Sydney J. Harris commonest quote

Though a quarrel in the streets is a thing to be hated, the energies displayed in it are fine; the commonest man shows a grace in his quarrel.
— John Keats

Buy good books, and read them; the best books are the commonest, and the last editions are always the best, if the editors are not blockheads.
— Lord Chesterfield

One of the commonest mistakes is thinking your worries are over when your children get married.
— commonest quotation by Kin Hubbard