I have stopped going to South Africa for any international conferences for mainly 3 things.
1. Border police rudeness: Some years ago I was invited for a conference on conflicts in the Horn in South Africa. I showed email invite to the border policeman at the desk. He rudely asked: "but why can't you people hold your peace conferences in your homes. Why always come to South Africa?" - I think he had a point. Why must we?
Second time it was worse - "But why are you Zomallis and Ethiopians always here."
I reminded him I was actually Kenyan, and I was only in the country for 2 days for an international conference
Reply: "Sheh, um, eh. But what is the difference"
2. As soon as locals figure out you are a black person, possibly African from another country, the automatic assumption is that you are an illegal migrant. You see immediate hostile reaction. Honestly, I found SA one of the most miserable places on earth in terms of peoples' attitude to foreigners. The visceral hatred towards fellow Africans is unnerving. Still one of the most beautiful geographies in Africa.
3. The state bureaucracy and departments filled with people who actually know very little about the outside world. Most of the best people who made South Africa an outward-looking African power are gone. All remaining are small-time apparatchiks stealing from the state and fat toads serving as diplomats. I feel sorry for South Africa.