Personality consists of the distinctive patterns of behaviour (including thoughts and emotions) that characterize each individuals adaptation to the situations of his or her life (Walter Mischel).
Type A personality
By nature Type A persons are competitive and hard-driving. Most of the time they are alert, competent, efficient people and can get things done on time. They look out for recognition and advancement, often involving themselves in multiple activities with deadlines. They live under constant pressure, most of which is self created. When subjected to a stress full situation out of their control, they are likely to become tense, anxious, impatient, hostile and disorganized.
Type B personality
Type B persons are exactly the opposite. They are easy going, less competitive and calm. They are more in control when subjected to a stressful situation.