Shortly after becoming president of Angola in September, Joao Lourenco did something completely unexpected: he stopped at a red light. The incident prompted thousands of social-media users to praise the former army general for abiding by the law. In October, Lourenco waited in line at a KFC outlet to buy a burger, and then earlier in January, photos surfaced of him and his wife, Ana Dias, strolling on a beach in the capital, Luanda. Few predicted the sharp contrast in leadership style with his predecessor, Jose Eduardo dos Santos, who rarely left the pink presidential palace from where he ruled Africa’s second-biggest oil producer for almost four decades. When he did emerge, hundreds of soldiers swarmed the city centre to allow his convoy to move swiftly through the pot-holed streets, leaving traffic paralysed for hours. "He’s been a very positive surprise," said Soren Kirk Jensen, an independent Angola expert. "There’s been a profound change of style, from a completely closed style...