I ate lunch at a restaurant in Lagos when I first arrived.  When they brought the bill they didn’t bring candies or fortune cookies……they brought 2 small bottles of liquid with a tiny glass and explained that the larger one was non alcoholic and the smaller one contained alcohol.  I was to drink whichever or from both….of course, I tried both.  My teachers explained that this was an old custom that most restaurants no longer do.  I guess I was lucky to have the experience.  I had seen other tables get blue and purple liquids…not sure if they tasted different.