Why do Westerners like to have parties while Chinese like to have dinners?
The primary purpose of a party is to satisfy the basic social need of human beings -- chatting. The secondary purpose is to drink, pick up girls and dance. Rare only a few friends in the local, to gather time to gather weekly chat, very difficult to gather, who knows who has which day which half a year ago on the calendar termin... To save the trouble, just set a regular time for all the free friends and friends of friends... If you're free that day, you're sure to meet someone else to chat with.