Sisters annoy, interfere, criticize. Indulge in monumental sulks, in huffs, in snide remarks. Borrow. Break. Monopolize the bathroom. Are always underfoot. But if catastrophe should strike, sisters are there. Defending you against all comers. – Pam Brown
Children of the same family, the same blood, with the same first associations and habits, have some means of enjoyment in their power, which no subsequent connections can supply… – Jane Austen, Mansfield Park, 1814