The funny thing about homeowner's associations is that most people buy homes in search of some control over their lives. When you're a renter, you generally have to abide by the rules set up by your landlord or superintendent. You usually have to put up with the wall colors they choose, the carpets they install, and so on. In your own home, you can change that stuff all you want.
A homeowner's association takes away a lot of that freedom. There must be a good reason why people join them though, right?