There is much to be said about personalities and their temperament. In fact, management banks on it with regards to their managerial staff, especially. Management has used Kepner-Tregore for critical-thinking processes for some time as well as Myers Briggs on personality types. The latter has been a reliable measurement of “know thyself” as an employee or on an individual basis.
The image below was the first working cover for the novel, CHOIR OF CLOISTERED CANARIES. They faced the Isthmus of Panama, their final destination. Their “contingencies” in the title had much to do with any contingency intended for use in circumstances not completely foreseen. There was no telling how their relationship would end after taking a bold step toward renewing their relationship.

The protagonist Leila, a scientist for the Centers for Disease Control and Prevention (U.S. CDC), she had been estranged from her mother Izobel for many decades and had finally wanted to reach out to her. Sort of as a catch-up measure, she had Izobel take the Meyers-Briggs personality type indicators. And she retook hers to see where she found her active temperament at the time only to discover that they were a match–the golden pair of INTP (Izobel) and her INFJ. They would finally understand each other, becoming compatible. Both of the golden pair are among the minority of minorities with INFJ being the rarest. Nonetheless, they suffered a gain albeit it was bittersweet at the start. These extremely rare personality types comprise up to 1-4% of the world population, according to the MBPI. Consequently, they tend to hold back from revealing their true selves for fear of being misjudged or misunderstood.
The IN indicators they have in common–“I” for introvert and “N” for intuitive. A few things that finally they discovered about themselves and their commonalities: They like their space and relating to their feeling of not quite fitting in with the world around them; their exploring non-traditional ideas, their discovering each other’s private quirkiness; and finally, they could respect each other. As for their opposite FJ and TP personality indicators, these helped them balance out their sensibilities and practicality. As for Drew, the male protagonist, he is an INTP. Lucky Leitis.

The chart below is a simple breakdown of the different indicator symbols, but take the key with a grain of salt, for the personalities of each run very deep and varied.
If you want to take a MBI test to see your personality type indicators, you can start out with this Personality Test. There are several online that are free.
Psychology is considered a pseudoscience. As a result, one needs to consider that one of the reasons for this designation is that there are too many variables that cannot be controlled to validate evidence. This type of test, however, is a good indicator of “who you are where you were when” that can help one to understand where one stands in a given point of time; in this case, the present situation and circumstances. One’s response mechanisms come to the fore. Sometimes it is difficult to find the demarcation of science and pseudoscience. In some instances, pseudoscience becomes science due to an improvement on methodology of evidence collected.