Why do you think people go to restaurants when they want to celebrate something? In my opinion, there are several reasons why people celebrate their significant events in restaurants. First of all, making arrangaments for parties by people themselves takes a lot of their time and, in the most cases make people nervous. Going to restaurants allow them to hang out with their friends in a little bit more relaxing way, because they do not need to bother about what kind of meals should be prepared, for instance. The second reason, I would say, it is because people want to change their envorinment during their celebration. It is quite normal that a person is accustomed to their apartaments or houses and it is difficult to have appropriate mood there. -- what else? ))