Self-service is a traditional element for humans. A typical and successful example of self-service is vendor machines that dispenses drinks. Coca-Cola (among others) operates a large number of self-service machines all over the world, in public places such as universities, museums, and sport arenas. People are used to dealing with the machines as they are simple to use and easy to find. In today’s world, there is a huge variety of self-service machines that are not limited to soft drinks. There are self-service machines for snacks, chewing gum and you can even buy pizzas from self-service machines.