The goal of a McDonald's is not to provide great food, nor to provide personal service. McDonald's definitely does not exist to expose people to new things. Instead, McDonald's and all fast food chains seek to churn out identical, predictable food, that will be turned out exactly the same whether you're in a small town in the Midwest or abroad in France. One way McDonald's revolutionized food production was to transform the restaurant into a sort of factory, an assembly line. Instead of a team of chefs working to prepare the food, the process of food production was broken down into a series of discrete steps, and a different person was devoted to each.
Every step is subject to strict control.
No matter where you are in the world, the grillman at McDonald's will always have the same number of hamburgers on the grill, and they will always be flipped in the same order. The person who assembles the hamburger will place the specified amount of ketchup, mustard and onion on each McBurger, so that all burgers end up being identical. The reduction of the cooking process in this way means that the human element is taken out of the process. There is no cook who experiments with different food preparations, there is no variation from company-specified procedures at all. This way, employees are easily replaced because their tasks are so standardized.