Discovered by an upholsterer who had to upholster the chairs in Dr. Meyer Friedman's office more, for he specialized in heart attack patients, who always sat on the edge of their seats, anxious to what would happen next. Type A personality is defined by three main traits...

  1. An exaggerated sense of time urgency
  2. Competitiveness and ambition
  3. Agressiveness and hostility, particularly when things get in their way.

source: Abnormal Psychology by Martin E. P. Seligman, Elaine F. Walker and David L. Rosenhan

(anyone find it funny the doctor's name is known but not the upholsterer?)