When you live in the West, there's always that moment that comes in neon, to remind you that you are not home. Forget that you are in the colour minority or even language. It is not when you constantly convert the local currency to Kenya shillings and cringe at how much you are paying for stuff - that, you expect.
It is what you do not expect that gets you. Culture shock can, of course, happen when you move to a different part of the continent, or country, but it is more dramatic away from the beloved Dark Continent.