Same But Different
In some ways we are all the same. We all have the same human nature. We share a common humanity. We all have human bodies and human minds, we all have human thoughts and human feelings.
Yet in other ways we are all completely different and unique. No two people are truly alike. No two people can ever have the same experience of life, the same perspective, the same mind.
Even identical twins are unique in this respect: twin number 1 will always be twin number 1 and will never know what it is actually like to be twin number 2, to experience life and see the world through number 2’s eyes.
See by Judith Rich Harris. 
Somewhere between these two — our common humanity and our unique individuality — lies personality.
Personality is about our different ways of being human. How we are all variations on the same themes. How the human nature we all share manifests in different styles of thinking, feeling and acting.
Personality can be defined in different ways, depending on whether we focus on the individual or on people in general.
If we focus on people in general, then we can define personality in terms of individual differences — that is, the range of different styles of thinking, feeling and acting.
Just as human beings can differ a great deal in terms of their physical traits (height, weight, hair, and so on), they also differ in terms of mental and behavioural traits. For example, some people are noticeably talkative and outgoing while others are noticeably quiet and reserved. Such differences and variations are seen everywhere throughout the human population.
If we focus on the personality of a specific individual, we can define it as that person’s particular set of enduring dispositions or long-term tendencies to think, feel and act in particular ways.
We’re not talking about specific actions being repeated again and again, like compulsive hand-washing, but about overall patterns, tendencies, inclinations. Someone who has tended to be quiet and reserved up to now will probably still tend to be quiet and reserved tomorrow. That doesn’t necessarily mean that they are compelled to be quiet and reserved at all times, in every possible situation. Rather, they are disposed to be be quiet and reserved more often than not.
We can also sometimes see changes in an individual’s personality over time. There may be subtle developmental changes during adolescence, for example, or there can be quite dramatic alterations following a massive brain injury.
Before we move on, here is a little puzzle to think about:
Is personality simply an umbrella term for all our dispositions (how we think and feel and act), or is it a ‘thing’ in its own right, a whole that is greater than the sum of its parts? Some psychologists see it one way and some see it the other way. For example:
“Your personality style is your organizing principle. It propels you on your life path. It represents the orderly arrangement of all your attributes, thoughts, feelings, attitudes, behaviors, and coping mechanisms. It is the distinctive pattern of your psychological functioning—the way you think, feel, and behave—that makes you definitely you.”
from by Oldham and Morris. 
In ancient times it was thought that all people could be divided into four basic — sanguine, choleric, melancholic and phlegmatic. This was supposedly something to do with the dominant fluids in their bodies (blood, yellow bile, black bile or phlegm).
This idea was briefly revived in Renaissance Europe and there are some modern versions of it around today.
see by Noga Arikha 
Despite the simple appeal of this approach, trying to fit all the world’s people with their amazing range of differences into so few boxes is not easy.
For example, ‘sanguine’ people are supposedly extroverted, creative, sensitive, compassionate, thoughtful, tardy, forgetful and sarcastic. But in fact there is no evidence that these characteristics go together at all. You can certainly be creative without being extroverted. You can certainly be compassionate without being sarcastic. So what does being ‘the sanguine type’ really mean, if anything?
Dividing people up into a few types may be a nice and simple way of looking at the world, but in reality it doesn’t get us very far.
A Thousand Words?
An alternative approach used by modern psychologists is to simply focus on the words we use to describe each other’s personalities. The idea that such words can tell us about personality, or at least how we conceive personality, is known as the .