When you say South Africa, Nelson Mandela is the name that instantly comes to mind. He was the face of Black Africa and under his wise guidance, the ANC came to power in 1994. And it has been downhill ever since.
Democracy throws up some weird characters to the highest positions of power, but ultimatley this is a reflection on the electorate's morality and intellect. Otherwise, how can we explain Narendra Modi's and Mayawati's re-elections in spite of what they have done, or rather not done?