no free lunch

What seems as a complimentary act in a restaurant often has a profit maximizing motive behind it. Three examples:

1- At a nice sushi restaurant, I was offered a glass of free chilled champagne before I even had a chance to sit down. Dry champagne is highly acidic and therefore quite appetite stimulating. After drinking a glass of it you end up ordering more food than you would otherwise have.

2- Many Turkish restaurants serve pickles before the meal. In fact, some of them keep pickles on their tables all the time. Pickles increase your appetite.

3- At an all-you-can-eat restaurant, right after settling down in our chairs, we got served four different varieties of breads and dips. The waiter explained us how each of these breads were of different cultural origin etc. Sophisticated? Yes. Interesting? No! They just wanted to get us full before we took a look at the buffet. Eating bread decreases your appetite. You end up eating less than you would otherwise have. That, of course, is in the interest of an all-you-can-eat restaurant.