Saying the whole of Africa is going a bit far. Many countries have some serious safety issues but not all. Ethiopia is a good example of somewhere that's pretty safe. Malawi is pretty good as well. In a lot of East Africa people generally aren't going to mess with you, a small bribe by a police officer is the most "violent" activity most tourists would encounter.

Having said that I'm always on my toes in South Africa and get quite nervous driving off the highway at night time outside certain parts of Johannesburg. Another place I never felt very safe was Manila, too many reports of taxi drivers robbing customers at knife or gunpoint.