The poor Em Dash is misunderstood.  Writers rarely remember he exists and, more frequently, confuse him for his cousin, En Dash.  Worse yet, people sometimes mistake him for his brother, Hyphen!  Every time he sees En Dash or Hyphen where he’s supposed to be, the poor guy curls up into a period or sags into a comma, and his tears are often dried up by his red-headed stepsister: Misplaced Semicolon.