Psychologist measured that people differ by personality, and can be roughly grouped into 16 categories based on traits. I used to think everyone was more or less the same. I'm not sure if 16 is the correct number. But my understanding of the world has been helped by the concept that there are people that do and act in particular patterns. For example some of the battles on twitter that are going on, are just extensions of these personality clashes.
I am myself very wary of this kind of personality tests but the case has been made in an interesting article that I can't seem to find that it is a form of "syntactic sugar" for the (apparently?) more established Big Five model. Anyways, I think OP's conclusion that it is eye opening that people have their own emotional structure/pattern of behavior from how they grew up and that you can find resembling patterns in different people quite reasonable.
Yes I was. But I'm also aware of the Big 5 personality traits. Openness, Conscientiousness, Extraversion, Neuroticism and Agreeableness. Which people seem to statistically group with some low or high mix of these traits.
Knowing that someone is more neurotic than 99% of other people, would seem on surface be useful in predicting how they might react to new or novel situations.
