Well, I would say that people who think “averages” does so as “national stereotipes”. For example, you tend to imagine german as blond and blue eyed, since that is the average there. If I were to imagine an African, it would depend on the part of Africa. Morocoon would be with arabic features, while nigeria would be black.

Os course history and migrations change the specific features if you know enough. In Spain is the same. People from the north usually are more light skinned (since there are less sun there) and you would see more blue and green eyes. Still not common, but not uncommon either.

At the end of the day I don’t think it matters that much. On the long run we all would be mixed race. At least if there are no artificial social barriers.