The psychology
Type A personalities are often associated with the following traits:
Drive, perfection, competitiveness, impatience, stress, ambition, and anxiety-prone.
Type B personalities are nearly the complete opposite.
The Type A and Type B personality theory was originally created by two cardiologists in the 1950's. The doctors were researching the possible causes of heart attacks in patients. Unsurprisingly, after a nine-year study (albeit with a small sample size), they concluded that those categorized as Type A carried a higher risk.
It is more likely that you will find a mix of both Type A and B character traits in yourself. For instance, perhaps you are an ambitious person who keeps a checklist of to-do's, but you are also often in a yoga studio and have a really great Instagram.
Type A personalities may be criticized for their sense of urgency and obsession with goals, but, hey, we get shit done.