I look at the political map of Africa, and I cringe. So many countries, borders all screwed up, countries inside countries, etc. And Sub-Saharan Africa is generally the poorest, least developed region in the world, from my understanding.
Yet South America is similar in climate and terrain, but today a political map of South America is border porn. To me, at least, it has a beautiful division of land between just a handful of nations, and while that continent certainly has its own problems, they aren't nearly as bad as Africa's. Why is this?
There are a lot reasons can be touched on. First, Africa is a far larger continent in terms of land mass, 11,608,000 Sq. Miles (30,065,000 Sq. Km) compared to South America at 6,880,000 Sq. Miles (17,819,000 Sq. Km). Colonizing powers also subdivided Africa among many different colonial powers compared to South America, so there is a far greater variance in administrative history. There are also more large ethnic groups in Africa than in South America. This should explain the variance in number of countries.
As far as "a messed up situation", there is endless things that could be said about that and it is hard to say anything without referring to vague generalities. One thing to keep in mind is that South American countries have existed for far longer than their African counterparts, so more time to build infastructure, gain administrative and political experience, less pure exploitation by colonizers, etc.