The knowledge of your temperament will help you become an attractive and happy personality.
On the foundation of biological temperament, you build spiritual character (the virtues).
Since Hypocrates and Galen we know there are 4 temperaments, which are related to the "humors": black bile (melancholic), yellow bile (choleric), phlegm (phlegmatic) and blood (sanguine). The Greeks were not mistaken about the existence of the 4 temperaments, although they were wrong about their origin (the theory of humors).