Origins in Africa

I was sitting on the subway last week looking at a couple of African-Americans, both in their 20s-30s. A particularly-dark skinned woman and a guy who had some features in common with Alonzo Mourning, the same regal cheekbones.  It occurred to me how pathetically unable I am to hazard much of a guess as to where people of sub-Saharan African descent hail from.  I mean, I know the difference between an Ethiopian and a West African, but from there it really goes downhill. Nothing compared to the level of phenotype consciousness I have for people of European descent or even East Asians, where I can pretty well differentiate between Chinese, Japanese, Koreans, etc. It is odd, given how much time I've spent living relatively near to Black people. But that's how we tag people in America.