We have a sloppy tendency to lump people into groups: white people, black people, gay, straight, immigrants, indigenous people, and so forth, as though people in those groups have the most in common by virtue of being labelled that way. But that’s generally false or overstated. Assuming no prohibitive language barriers, then from my experience of people, the factor that most determines what they have in common is not skin colour, ethnicity or sexuality, it is their level of education.
People functioning and performing at a similar educational level have shared
frameworks that far exceed other commonalities. A highly educated black woman
and a highly educated white man usually have more in common than a highly
educated black woman and a very uneducated black woman. Education often gives
people a more common vocabulary, worldview, and analytical approach. Education
also often determines which media, literature, and historical frameworks people
are familiar with, as these become influential points of connection. Also, many
social behaviours, expectations, and conversational styles tend to be shaped by
education, which makes interactions more fluid within similar levels. And also,
education strongly influences income level, job type, and social mobility –
which, of course, affects social circles, lifestyle, housing, health, and
community involvement.
There are exceptions, of course – people with similar levels of education can have different upbringings and values, different temperaments and worldviews – but I think education is one of the strongest predictors of shared worldview, especially in modern societies, as it most heavily intersects with other deep influences like communication, values, culture, family, and class.