One of the most popular … in human culture is to understand ourselves, starting with our own personality.
Yet, what IS personality? 
Personality is the expression of ourselves in the world, and consists of the qualities and characteristics which are available to organize as a person, or within a person.
The word personality comes from the Greek word persona, which means mask. Personality is not like a mask, because it changes, and (when authentic) it does not try to hide.
Personality is often broken down into “types”. There are many ways that are used, and some of these are more useful than others.
We decide our personalities every minute. Sometimes we are courteous, sometimes we are impatient. We can, using brain and mind plasticity, change our reactions to situations. In doing this, we can change our personality.