Why so many coup d'etat's in Africa?

Many look at the African continent and shake their heads. It's too complicated, too volatile, ever changing to understand. But what accounts for this volatility? Why has the African continent been so unstable -- politically, economically, and militarily?

Some theorists suggest that it has to do with colonial legacies. If you want to understand why the African continent -- over four decades after independence continues to be so underdeveloped, politically and economically -- turn to colonial legacies. Artificial states, a focus on politicized ethnicity, regionalism -- all of these factors are negative legacies of colonialism. But what about bad political leadership? The African continent has had its share of the Idi Amins, the Bokassa's, the Mobutu's and the Mugabe's. Why has this continent suffered so much for so many years? Is there something unique to the African continent? The African people? African society? Or are the problems of coups d'etats just the process of development?
And what can be done? Should Africans have to deal with continual political upheaval, or has a page been turned in African history? Has the democratic flower taken root in African soil?