The problem with homeowners' associations is that there are two kinds of people: those who think a yard is for looking at and those who think a yard is for using. People who like to look at yards understandably like them to be neat and pretty, uncluttered, fully landscaped, and think that all the yards they can see should meet the same criteria. These are generally calm adults who use their house for sleeping and eating; the rest of their life happens elsewhere. This aesthetic appeals to the hyper-hygenic, orderly, even sterile tastes of the (aspiring) upper middle class, so it tends to be imposed on other people in the newer subdivisions.
People who like to use their yards think that pretty is nice but that uncluttered ain't gonna happen; yards are for playing and working in, not just looking at. Yards hold on-going projects, bike and ski jumps, toys, and anything too big for the house. In our immediate neighborhood, we are the only house with kids and the only ones who apparently make use of their yards; in addition to the relatively non-offensive compost heap, we have forts made of old fence rails, bike jumps, occasional obstacle courses, and, in the summer, a tent trailer for guests (since we don't have a guest room). Luckily, our immediate neighbors enjoy seeing the kids out playing, so we don't have a problem. We also have a pretty tolerant set of covenants, much more accepting of yard activities than many I heard about; at least we can have home-built forts, patches of unmowed field, and a woven-wire fence to keep our dogs in. But in many places, the clean-yard brigades have won the covenant battles and people who want to use their yards are out of luck.